Federal Motor Vehicle Safety Standards; Child Restraint Systems; Child Restraint Anchorage Systems
Federal RegisterMar 5, 1999
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SUMMARY: This final rule establishes a new Federal motor vehicle safety
standard that requires motor vehicle manufacturers to provide motorists
with a new way of installing child restraints. In the future, vehicles
will be equipped with child restraint anchorage systems that are
standardized and independent of the vehicle seat belts.
The new independent system will have two lower anchorages, and one
upper anchorage. Each lower anchorage will include a rigid round rod or
``bar'' unto which a hook, a jaw-like buckle or other connector can be
snapped. The bars will be located at the intersection of the vehicle
seat cushion and seat back. The upper anchorage will be a ring-like
object to which the upper tether of a child restraint system can be
attached. The new independent anchorage system will be required to be
installed at two rear seating positions. In addition, a tether
anchorage will be required at a third position. This final rule also
amends the child restraint standard to require child restraints to be
equipped with means for attaching to the new independent anchorage
system.
This final rule is being issued because the full effectiveness of
child restraint systems is not being realized. The reasons for this
include design features affecting the compatibility of child restraints
and both vehicle seats and vehicle seat belt systems. By requiring an
easy-to-use anchorage system that is independent of the vehicle seat
belts, this final rule makes possible more effective child restraint
installation and will thereby increase child restraint effectiveness
and child safety.
Issuance of this rule makes the United States the first country to
adopt requirements for a complete universal anchorage system. To the
extent consistent with safety, NHTSA has sought to harmonize its rule
with requirements being considered by standard bodies and regulatory
authorities in Europe and elsewhere. The agency has harmonized with
anticipated Economic Commission for Europe and Canadian regulations by
requiring that bars be used as the lower anchorages for installing
child restraints. The agency has also harmonized with Canadian and
Australian regulations by expressly requiring tether anchorages in
vehicles and indirectly requiring tethers on most child restraints.
For the convenience of the traveling public, DOT wants child
restraints complying with this final rule to be usable in both aircraft
and motor vehicles to the extent practicable. To that end, the agency
is developing a proposal to ensure that the new child restraints are
not designed in a way that might make them unsuitable for aircraft use.
NHTSA expects to issue the proposal next spring.
DATES: The amendments made in this rule are effective September 1,
1999.
The incorporation by reference of the material listed in this
document is approved by the Director of the Federal Register as of
September 1, 1999.
Petitions for reconsideration of the rule must be received by April
19, 1999.
ADDRESSES: Petitions for reconsideration should refer to the docket
number of this document and be submitted to: Administrator, Room 5220,
National Highway Traffic Safety Administration, 400 Seventh Street
S.W., Washington, D.C., 20590.
FOR FURTHER INFORMATION CONTACT: For nonlegal issues: George
Mouchahoir, PhD. (202-366-4919), Office of Crashworthiness Standards,
NHTSA.
For legal issues: Deirdre R. Fujita, Office of the Chief Counsel
(202-366-2992), NHTSA.
Both of the above persons can be reached at the National Highway
Traffic Safety Administration, 400 Seventh St., S.W., Washington, D.C.,
20590.
SUPPLEMENTARY INFORMATION:
Table of Contents
I. Executive Summary of this Final Rule
a. Final rule
b. Why NHTSA is issuing this rule: the underlying issue, and how
this rule addresses it
c. How and why this final rule differs from the agency's NPRM:
particularly, why NHTSA selected the ISO rigid bar anchorage system,
instead of the flexible latchplate anchorage system
d. Future proposal to promote the usability of the new child
restraints in both aircraft and motor vehicles
II. Safety Issue
a. Why is something being done to improve child restraint
safety? Aren't child restraints highly effective already?
b. Factors affecting child restraint effectiveness
III. Summary of the NPRM
a. What NHTSA proposed to address the issue; preference for
flexible latchplate anchorage system over the rigid bar anchorage
system
b. Proposed leadtime
c. NPRM's estimated benefits and costs of the rulemaking
d. Alternatives considered
IV. Summary of the Comments
a. Commenters supporting flexible latchplate anchorage system
b. Commenters supporting rigid bar anchorage system
V. Summary of Post-Comment Period Events and Docket Submissions
a. ISO working group refines and completes draft ISO standard on
rigid bar anchorage system
b. Child restraint manufacturers shift support to rigid bar
anchorage system
c. Industry conducts consumer focus group testing on which lower
anchorage system is preferred
d. Canada issues rule on tether anchorages
VI. Agency Decision Regarding Final Rule
a. Summary of the final rule
b. Summary of key differences between NPRM and final rule
VII. Issue-by-Issue Discussion of the Agency Decision on Content of
Final Rule
a. NHTSA determines the anchorage systems are essentially equal
on the merits
b. There is substantial consumer interest in both anchorage
systems
c. NHTSA determines only one lower anchorage system can be
selected
d. NHTSA selects the rigid bar anchorage system based on its
advantages over the flexible latchplate anchorage system
1. The first advantage is harmonization of standards
2. The second advantage is enhanced design flexibility which
provides a reasonably predictable prospect for design improvements
that will enhance either safety or public acceptability or both
3. The third advantage is possible safety benefits
e. NHTSA's final rule is not identical to the draft ISO standard
1. Bars may not be attached to the vehicle by webbing materials
2. The bars must be visible or the vehicle seat back marked to
assist consumers in locating them
3. A tether anchorage is not required by the draft ISO standard,
but is required by this final rule
f. The types of vehicles that are subject to the adopted
requirements
g. The number of anchorage systems that are required in each
vehicle
h. Lockability requirement will be retained until 2012
i. Strength requirements for lower rigid bars of child restraint
anchorage system and compliance test procedures
j. Requirements for child restraints
k. Performance and testing requirements for tether anchorages
l. Leadtime and phasing-in the requirements
[[Page 10787]]
1. Tether anchorage and tether strap
2. Lower anchorage bars and means for attaching child restraints
to those bars
3. Requirement to identify vehicles certified to the vehicle
requirements during the phase-in
VIII. Rulemaking Analyses and Notices
a. Executive Order 12866 (Federal Regulation) and DOT Regulatory
Policies and Procedures
b. Regulatory Flexibility Act
c. Executive Order 12612
d. Unfunded Mandates Reform Act
e. National Technology Transfer and Advancement Act
f. National Environmental Policy Act
g. Executive Order 12778 (Civil Justice Reform)
h. Paperwork Reduction Act
I. Executive Summary of This Final Rule
a. Final Rule
Child restraint systems are highly effective in reducing the
likelihood of death or serious injury in motor vehicle crashes. The
agency estimates that child restraints are potentially 71 percent
effective in reducing the likelihood of death.1 However, the
extent to which this level of effectiveness is achieved in actual use
depends upon a number of factors, including how well motorists are able
to adapt the vehicle seat belts for the installation of the child
restraints, and upon the compatibility between child restraints and
vehicle seats and seat belts. As a result of improper installation of
children in child restraints and child restraints in vehicles, the
actual average effectiveness for all child restraints in use in
preventing fatalities is 59 percent.2
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\1\ Kahane, Charles J. (1986), An Evaluation of the
Effectiveness and Benefits of Safety Seats, U.S. Department of
Transportation, National Highway Traffic Safety Administration, DOT
HS 806 889, p. 305. The agency believes that this figure remains
valid.
\2\ Hertz, Ellen (1996), Research Note, ``Revised Estimates of
Child Restraint Effectiveness,'' U.S. Department of Transportation,
National Highway Traffic Safety Administration.
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This final rule will improve the actual average effectiveness of
child restraint systems by improving the compatibility of child
restraints and vehicles and making them easier to install. This rule
requires that motor vehicles be equipped with a easy-to-use anchorage
system designed to be used exclusively for securing child restraints.
Each vehicle anchorage system will consist of an upper anchorage point
and two lower anchorage points. Each lower anchorage includes a 6
millimeter (mm) (0.24 inches (in.)) diameter straight rod, or ``bar,''
that is attached to the vehicle and is lateral and horizontal in
direction. The bars are located near the intersection of the seat
cushion and seat back in a position where they will not be felt by
seated occupants. The upper anchorage is a user-ready component for
attaching the top tether of a child restraint. This preamble refers to
this system as the ``rigid bar anchorage system,'' in reference to the
6 mm diameter bars, which are rigidly mounted to the vehicle.
Each vehicle must have at least two vehicle anchorage systems
rearward of the front seat. However, if a vehicle has a rear seat with
insufficient space to accommodate a rear facing infant seat, and is
equipped with, as original equipment (OE), an air bag cutoff switch
that deactivates the air bag for the front passenger position, one
anchorage system must be provided in that position, and another in a
rear seating position to accommodate a forward-facing child
restraint.3 If a vehicle has no rear seat, and is equipped
with an OE air bag cutoff switch that deactivates the air bag for the
front passenger position, one anchorage system must be provided in that
position.
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\3\ The anchorage for a front seat tether could be attached any
one of three places: the ceiling; the floor pan right behind the
front seat; or to the back of the lower part of the seat structure.
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Each vehicle with at least three rear designated seating positions
must also have a third rear designated seating position equipped with a
user-ready tether anchorage. The third tether anchorage provides
parents an improved means of attaching the new child restraints at a
third rear seating position. In a typical family car with three rear
seating positions, the third tether anchorage would likely be at the
center rear seating position, which is a seating position that many
parents prefer placing their child. A full child restraint anchorage
system (consisting of the two rigid bars for the lower anchorages and a
top tether anchorage) is not required to be installed in the center
rear seating position because it may be difficult to fit the lower
anchorages of two child restraint anchorage systems, or two child
restraint systems, adjacent to each other in the rear seat of small
vehicles. Further, a lap belt at the center rear seating position,
together with a tether anchorage at that position, should perform
essentially as well as a full child restraint anchorage system. For
these reasons, and to minimize the cost of facilitating the use of the
new child restraints in the third position, the agency is requiring
two, and not three, child restraint anchorage systems.
Each child restraint will have components, such as hooks or
buckles, that are designed to clasp to the two lower rigid bars of a
vehicle's rigid bar anchorage system. Although the final rule does not
expressly require child restraints to have top tethers, it establishes
stricter limits on the distance that the head of a dummy seated in a
child restraint may move forward during a test simulating a frontal
vehicle crash (head excursion limit). Almost all child restraint models
will likely be equipped with a top tether in order to comply with the
new head excursion limit.
Each child restraint will also have to continue to be capable of
being attached to a vehicle by way of the vehicle's belt system. This
way, child restraints that have the new components can still be used on
older model vehicles that do not have a child restraint anchorage
system. Child restraints with the new components can also still be used
on aircraft, using the aircraft belt system to attach to the aircraft
seat. Older model child restraints that do not have the new components
attaching to the child restraint anchorage system can use vehicle
belts, as child restraints do now, to attach to new vehicle seats that
have a child restraint anchorage system.
The requirements adopted today reflect a worldwide effort to
improve the installation of child restraints in motor vehicles. This
final rule uses the technical specifications set forth in a draft
standard being developed by a working group to the International
Organization for Standardization (ISO), a worldwide voluntary
federation of ISO member bodies. NHTSA anticipates that the ISO, which
began work on an independent child restraint anchorage system in the
early 1990's, will be adopting the draft standard as a final standard
within the next year. Incorporation of the ISO standard into the
regulations of the European community is likely to follow. Canada and
Australia have also indicated their intent to undertake regulatory
action aimed at requiring the rigid bar anchorage system to improve
child restraint attachment for their countries' children.
NHTSA is issuing this final rule at this date, prior to the ISO's
completion of work on the draft standard, in order to provide increased
safety to this country's children as quickly as possible. Further, the
agency anticipates that the ISO and the working group will not make
significant changes to the draft ISO standard. To the extent that the
final ISO standard differs from this final rule, the agency will
evaluate those differences to determine if changes to this final rule
appear warranted. In the event NHTSA tentatively determines
[[Page 10788]]
that changes may be warranted, the agency will commence a rulemaking
proceeding and make a decision as to the issuance of an amendment based
on all available information developed in the course of that
proceeding, in accordance with statutory criteria.
b. Why NHTSA Is Issuing This Rule: The Underlying Issue, and How This
Rule Corrects It
This rule makes it easier to install child restraints by
eliminating the current dependence of motorists on vehicle seat belts
as the means of installing child restraints in vehicles. The primary
purpose of seat belts has always been to protect older children,
teenagers and adults from serious injury in vehicle crashes. A
secondary purpose of seat belts has been to install child restraints in
vehicles.
Attempting to design seat belts to achieve the first purpose
(restraining older children, teenagers and adults) has sometimes led to
design choices that may have made it more difficult for the belts to
achieve the second purpose (tightly securing a child restraint). One
design change is the replacement of simple lap belts with integrated
lap/shoulder belts in the back seats of vehicles. Another change is the
positioning of some seat belt anchorages several inches forward of the
seat back to better position the lap belt low on the pelvis of these
occupants. While these and other design changes have increased the
ability of vehicle belt systems to restrain occupants, they have made
it harder for motorists to use the belts on some vehicles for
installing child restraints.
By requiring motor vehicles to be equipped with standardized
anchorages designed exclusively for the purpose of securing child
restraints, this final rule will help vehicle and seat belt
manufacturers design belts to more effectively perform a dual role.
Manufacturers will be able to optimize seat belts to restrain older
children, teenagers and adults. Further, the final rule will provide
motorists with a means of securing child restraints that is easier and
more effective.
By requiring an independent child restraint anchorage system, the
final rule improves the compatibility of vehicle seats and child
restraints and the compatibility of seat belts and child restraints.
Installation of the new system will result in more child restraints
being correctly installed. The standardized vehicle anchorages and the
means of attachment on child restraints are intuitive and easy-to-use.
For example, they eliminate the need to route the vehicle belt through
or around the child restraint. By making child restraints easier to
install, correct use and effectiveness will be increased.
The requirement for top tether anchorages in vehicles will be
implemented before the requirement for the lower vehicle anchorages
since less leadtime is needed for the installation of the tether
anchorages. In those vehicles equipped with tether anchorages but not
lower anchorages, owners can install a child restraint complying with
this rule by attaching the tether and using the vehicle seat belts to
secure the lower part of the child restraint. Tether anchorages will be
required in the vast majority of passenger cars beginning September 1,
1999 4, and in all light trucks, buses and multipurpose
passenger vehicles beginning September 1, 2000. To provide consumers
with the standardized lower anchorages in vehicles as quickly as
possible, this rule specifies a three year phase-in that begins
September 1, 2000. Beginning on that date, this rule requires vehicle
manufacturers to begin installing the new lower anchorages in new
passenger cars, in trucks and multipurpose passenger vehicles with a
gross vehicle weight rating (GVWR) of 3,856 kilograms (kg) (8,500 lb)
or less, and in buses with a GVWR of 4,536 kg (10,000 lb) or less
(including school buses in that GVWR category). Beginning on September
1, 2002, the new lower anchorages will be required in all new vehicles
in those categories.
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\4\ The requirement will be phased in, with 80 percent of a
vehicle manufacturer's passenger car fleet required to have user-
ready tether anchorages by September 1, 1999, and the remaining 20
percent required to comply September 1 of the following year.
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The requirement (the stricter head excursion limit) that will cause
top tethers to be installed on most child restraint systems will be
effective September 1, 1999. The requirement for child restraints to be
equipped with means for attaching to the lower anchorages will be
effective September 1, 2002. NHTSA believes that the latter requirement
should not be phased-in. Child restraint manufacturers have informed
the agency that a phase-in would not be successful because they do not
have the same type of control over the distribution of their products
that vehicle manufacturers have. According to the child restraint
manufacturers, if they were to produce both current child restraint
systems as well as child restraints with the new attachments,
distributors and retailers of their products would order mainly the
current child restraints to sell, which do not have the new
attachments, and not the new restraints because the current systems
would cost less than the new child restraint systems. Further, NHTSA
has decided against requiring all new child restraints to have the new
attachments earlier than the date on which vehicles will be equipped
with the lower anchorage system because new vehicles equipped with the
new attachment system will be a small proportion of the total vehicle
fleet during the phase-in period. Nevertheless, the agency anticipates
that some child restraint manufacturers will begin offering new designs
during the phase-in period, to meet a market demand for the products.
c. How and Why This Final Rule Differs From the Agency's NPRM:
Particularly, Why NHTSA Selected The ISO Rigid Bar Anchorage System,
Instead of the Flexible Latchplate Anchorage System
Today's final rule adopts the key aspect of the proposal. As in the
proposal, this rule requires vehicles to be equipped with an
independent anchorage system for attaching child restraints. An
independent system is strongly preferred by consumers over current seat
belts as the means of attaching child restraint systems. The
independent system uses three attachment points for securing a child
restraint to a vehicle seat (the two lower anchorages and the top
tether). The two lower points are at or near the intersection of the
vehicle seat cushion and seat back.
However, this final rule differs from the proposed system in
several important respects. The agency proposed to permit either of two
lower anchorage systems for vehicles: (1) the rigid bar anchorage
system adopted in this final rule; or (2) a buckle and flexible
latchplate system known as ``the uniform child restraint anchorage
system'' (``UCRA'' system). The buckle and latchplate of the second
system are similar to what is used for adult seat belts in vehicles.
The two lower anchorages consist of small latchplates, attached to
flexible webbing, near the intersection of the vehicle seat cushion and
seat back. (In reference to the latchplates and to the flexibility of
the webbing, hereinafter this preamble refers to the UCRA system as the
``flexible latchplate system.'' This is to provide a more descriptive
term for the system than ``UCRA,'' for the reader's convenience.)
Buckles designed to attach to the latchplates are attached to the child
restraint by belt webbing.
Both systems would have been permitted under the NPRM because each
had its advantages. At the time of the proposal, information available
to NHTSA indicated that the installation of
[[Page 10789]]
the flexible latchplate system, instead of the rigid bar anchorage
system, in motor vehicles would result in less added cost and weight
for child restraints. This information was contained in a study
performed by a contractor for NHTSA. At the time of that study, the
then-existing prototypes of child restraints made to connect with the
rigid bar anchorage system were significantly different from current
prototypes. The then-existing prototypes typically had rigid prongs, or
runners, for attaching the child restraints to the rigid bars and a
substantial (and therefore heavy) supporting structure for the runners.
Based on that information from the study, the agency's cost analysis
indicated that the buckles of the flexible latchplate system (which
were attached to the child restraint by means of webbing) would add an
estimated $14 to the cost of a child restraint, while the rigid prongs
(attached by means of a heavy base) would add $60 to $100 to the cost
of a child restraint.
Although the two systems appeared to have similar safety benefits,
the lower anchorage of the flexible latchplate system appeared to
necessitate making less costly changes to child restraints than the
rigid bar anchorage system. Accordingly, the agency gave preference to
the flexible latchplate system in its proposal. It did this by
proposing to require that all child restraints have the buckles for
attaching to the flexible latchplate system. The rigid bar anchorage
system could have been provided only if the vehicle manufacturer also
provided an adapter that would connect at one end to the rigid bar and
at the other end to the buckles on the child restraint.
The agency has decided to require the installation of rigid bar
anchorage systems in motor vehicles instead of permitting either those
systems or flexible latchplate anchorage systems. Commenters urged
NHTSA to mandate a single system because of their opposition to an
adapter. They believed that an adapter would be lost or misused by
consumers, resulting in buckle-equipped child restraints unable to use
or improperly using a rigid bar anchorage system in the vehicle.
Further, the agency notes that mandating a single system standardizes
the anchorage system and thereby promotes consumer understanding of and
familiarity with the system.
In deciding which system to select, NHTSA noted that the rigid bar
anchorage system and the flexible latchplate system appear to be
roughly equally acceptable to the public. ISO-reported consumer clinics
that were conducted overseas and in Canada indicated comparable levels
of consumer acceptance for the two systems. In the most recent consumer
preference clinic, which was sponsored by U.S. and foreign vehicle
manufacturers, child restraint designs that were compatible with the
rigid bar anchorage system and with the flexible latchplate system were
strongly preferred over current child restraints designs that use
vehicle seat belts to attach to the vehicle. While consumers scored the
child restraint design that had the buckles highest, the three systems
that had the rigid bar anchorage-type of child restraints were, in
aggregate, the first choice of a large number of participants. This
does not mean that the consumers selected the rigid bar over the
flexible latchplate as their preferred vehicle system. However, it does
appear to indicate that the design flexibility of the rigid bar system
accommodated a variety of child restraint attachment options that, in
aggregate, resulted in more ``first place'' finishes than the flexible
latchplate design.
The agency also noted that when the flexible latchplate lower
anchorage system is compared to new prototypes of child restraints
designed to attach to rigid anchorages, the flexible latchplate system
loses much or all of the cost and weight advantage it was thought to
have at the time of the NPRM. After the NPRM was published, a number of
child restraint and vehicle manufacturers determined that child
restraints need not have rigid runners to attach to the rigid bar
anchorage system. They told the agency that hooks and other devices
were viable alternatives to rigid runners, and would be used by most
child restraint manufacturers if the rigid bar anchorage system were
adopted. They said that the hooks and other alternative connectors
could be attached to the child restraint with belt webbing, in the same
way the buckles for the flexible latchplates can be attached to the
child restraint. New analysis by the agency indicates that these
alternative rigid bar anchorage connectors would cost about the same or
less than the flexible latchplate buckles, and would not add
substantial bulk or weight to child restraints.
The rigid bar anchorage system currently has fairly wide support
among both vehicle and child restraint manufacturers. In June 1996, the
flexible latchplate anchorage system was supported by a wide variety of
vehicle manufacturers (virtually all domestic and foreign vehicle
manufacturers except for European manufacturers) and child restraint
manufacturers. Now, however, the only major vehicle manufacturer on
record with this agency as expressly favoring the flexible latchplate
anchorage system is General Motors. The shift to the rigid bar
anchorage system began shortly before publication of the NPRM. At that
time, Ford and Chrysler announced that they had changed their support
to the rigid bar anchorage system. Recently, Toyota expressed support
for the rigid bar anchorage system. In addition, most child restraint
manufacturers now support the rigid bar anchorage system.
Manufacturers cited the potential advantages of the rigid bar
anchorage system over the flexible latchplate system. They believe that
the rigid bar anchorage system will further international harmonization
of safety standards, while the flexible latchplate system will not.
They also believe that the rigid bar anchorage system allows for
greater design flexibility than the flexible latchplate system in the
design of child restraints and the connectors used to attach to the
anchorage system. They also believe that the rigid bar anchorage system
will enhance safety better than the flexible latchplate system in side
impacts, when rigid attachments are used on the child restraint to
connect to the rigid 6 mm bars in the vehicle seat bight (the
intersection of the seat cushion and the seat back). Many supporters of
the rigid bar anchorage system cite test data that show that the system
prevented head contact between a test dummy and the door structure in
side impact simulations, while the flexible systems did not. Some child
restraint manufacturers also believe that rigid attachments on both the
vehicle and the child restraint could better limit head excursions of
older children in frontal impacts.
NHTSA's selection of the rigid bar anchorage system harmonizes this
final rule with the actions of other regulatory authorities around the
world. Further, today's final rule adopts best practices in what has
been a global effort to develop an effective and easy-to-use child
restraint anchorage system. The rigid bar anchorage system is the one
most likely to be chosen as an internationally harmonized design under
the auspices of the United Nations Economic Commission for Europe.
Canada is also in support of the rigid bar anchorage system and may be
adopting the system in the future. This final rule also harmonizes with
Canadian and Australian regulations by expressly requiring tether
anchorages in vehicles and indirectly requiring tethers on most child
restraints.
Harmonizing this rule with the actions of other international
bodies is consistent with the goals of the Trade
[[Page 10790]]
Agreements Act of 1979, as amended (July 26, 1979, Public Law 96-39,
section 1(a), 93 Stat. 144.) (19 U.S.C. 2501 et seq.). That Act
requires, inter alia, Federal agencies to take into consideration
international standards and, if appropriate, base the agencies'
standards on international standards. The harmonization achieved by
this rule permits vehicle and child restraint manufacturers to have a
greater measure of planning certainty and predictability in designing
and selling their products, helps ensure that parents are provided an
anchorage system that meets their safety needs at the lowest possible
cost, and eliminates a potential barrier to international trade.
d. Future Proposal To Promote the Usability of the New Child Restraints
in Both Aircraft and Motor Vehicles
As NHTSA noted in its February 1997 NPRM, the Federal Aviation
Administration (FAA) is concerned that some new child restraints might
be manufactured with rigid ISO connectors or prongs that are neither
foldable nor retractable. FAA believes that if a child restraint with
non-folding, non-retracting rigid connectors were installed on an
aircraft seat, the connectors or prongs might damage the aircraft seat
cushions. They could also protrude into the leg space and egress path
of the passengers sitting in the row immediately behind the seat.
NHTSA believes that the near-term prospect of child restraint
manufacturers producing child restraints with non-folding,
nonretractable rigid connectors is fairly remote. Most child restraint
manufacturers are not using rigid connectors in their prototype
development work. The one manufacturer focusing on rigid connectors has
been using retractable rigid connectors or prongs in its product
development work.
Nevertheless, the issue of child restraint/aircraft compatibility
and consumer convenience is an important concern to NHTSA and FAA. The
two agencies want parents to be able to buy a single child restraint
that can be used in aircraft as well as in motor vehicles. To that end,
NHTSA is developing a proposal to ensure that the new child restraints
are not designed in a way that might make them unsuitable for aircraft
use. The proposal would require that if a child restraint has rigid
connectors, they must be foldable or retractable. As an alternative,
the agency would propose to require foldability or retractability as a
condition to certifying child restraints with rigid connectors for
aircraft use. NHTSA expects to issue the proposal this spring.
II. Safety Issue
a. Why Is Something Being Done To Improve Child Restraint Safety?
Aren't Child Restraints Highly Effective Already?
NHTSA estimates that, when installed correctly in a vehicle with
compatible seating and seat belt systems, child restraints are 71
percent effective in reducing the likelihood of death in motor vehicle
crashes. However, as a result of many child restraints either not being
used correctly or installed in vehicles with seats or seat belts that
are not fully compatible, the actual average effectiveness for the
entire population of child restraints in use is 59 percent.
5
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\5\ Hertz (1996), supra.
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b. Factors Affecting Child Restraint Effectiveness
The estimated 71 percent level of effectiveness is not realized in
many cases for several reasons. Currently, the standardized means of
attaching a child restraint is the vehicle belt system. Over the years,
vehicle seats and belt systems evolved to better restrain the upper and
lower torsos of older children, teenagers and adults. For example, seat
belt anchorages are sometimes positioned several inches forward of the
seat back to better position the lap belt low on the pelvis of these
occupants. The need to design vehicle seat belts to perform the dual
functions of restraining child restraint systems and of restraining the
torsos of older children, teenagers and adults limits the extent to
which vehicle belts can be designed to promote the effectiveness of
child restraints.
To elaborate further on the example given above regarding seat belt
anchorages, when vehicle belts attached to forward-mounted seat belt
anchorages are used with a child restraint, the belts cannot initially
provide any resistance to the forward movement of a child restraint in
a frontal crash. The child restraint slides forward in a crash until
the belt finally resists the forward movement of the child restraint.
NHTSA estimates that seat belt anchorages positioned five or more
inches forward of the seat back can increase the probability of severe
or greater injury by over 11 percent. This final rule makes child
restraints safer by reducing the likelihood of increased forward
movement of the child's head, and the likelihood of head impact, and
other traumas.
Other examples of the need to improve the compatibility of child
restraint systems and vehicles include:
(1) The seat cushions and seat backs are deeply contoured. This
improves the comfort of seated passenger and helps keep belted
passengers in place, but limits the ability of the seat to provide a
stable surface on which the child restraint can rest. This final rule
will make child restraints more stable, regardless of the contours of
the seat and seat back.
(2) The length of some seat belts and accompanying hardware
attachments are not suitable for use with child restraints, or with
special child restraints. In some seating positions, the distance
between the anchorages for the lap belt and buckle is not as wide as a
child restraint. In these cases, the seat belt may not tightly hold the
child restraint and it can easily move from side to side. By providing
a means for attaching child restraints that is independent of the
vehicle belts, this final rule will improve the lateral stability of
child restraints on the vehicle seat.
(3) Some vehicle seats are not wide enough or long enough to
accommodate child restraints properly. This final rule will accommodate
child restraints on these seats by providing an independent means of
stability.
Efforts to make vehicle belt systems more effective for teenagers
and adults have also resulted in the belt systems becoming more
complex. Lap/shoulder belts replaced lap belts. On older vehicles,
these belts need to be used with an accessory item, such as a locking
clip, for use with child restraints. A locking clip impedes movement of
the sliding latchplate on the lap/shoulder belt, which better restrains
a child restraint when the car is maneuvering or changing its velocity.
Since September 1, 1995, lap belts on new passenger vehicles are
lockable without a locking clip, but the belt must be maneuvered in a
special manner not always understood by consumers to engage the locking
feature.
Due in part to these complexities, the rate of incorrect usage of
child restraints is high. A four-state study done for NHTSA in 1996
examined people who use child restraint systems and found that
approximately 80 percent of the persons made at least one significant
error in using the systems. (``Patterns of Misuse of Child Safety
Seats,'' DOT HS 808 440, January 1996.) Observed misuse due to a
locking clip being incorrectly used or not used when necessary was 72
percent. Misuse due to the vehicle seat belt being incorrectly used
with a child seat (unbuckled, disconnected, misrouted, or untightened)
or used with a child too small to fit the belts was 17 percent.
[[Page 10791]]
People are not only not using child restraints as correctly as they
should, they are also frustrated with the effort needed to attach a
child restraint. Consumer clinics conducted in the U.S.6 and
Canada 7 found that virtually all the people surveyed in the
studies expressed high levels of dissatisfaction with conventional
means of attaching child restraints in vehicles. NHTSA's Consumer
Complaint Hotline received approximately 19,792 calls in 1996, 10,326
calls in 1997, and 19,935 in eight months in 1998, from people asking
about child seat compatibility with a particular vehicle or how to
correctly install a child seat, including requests for step-by-step
guidance in installing their child seats. When an article appears in
the media about compatibility problems between child restraints and
vehicle seats, those calls typically increase to over 500 a day.
---------------------------------------------------------------------------
\6\ ``An Evaluation of the Usability of Two Types of Universal
Child Restraint Seat Attachment Systems,'' General Motors
Corporation, 1996.
\7\ ``The ICBC Child Restraint User Trials,'' Rona Kinetics and
Associates Ltd. Report R96-04, prepared for the Insurance
Corporation of British Columbia, December 1996.
---------------------------------------------------------------------------
NHTSA is concerned that because of frustrations associated with
vehicle to child restraint compatibility problems and the difficulties
with installing child restraints, consumer confidence in the safety of
child restraint systems could be eroding. A consumer clinic held in
April 1998 showed that the number one consumer safety concern was with
how tightly (secure) participants could get the child restraint
installed in the vehicle. NHTSA estimates that about 35 percent of the
rear seats of new passenger cars having seat belt anchorages 4 inches
or more away from the seat bight. The agency is concerned that
declining consumer confidence in child restraint systems could result
in less use of child restraints. Being able to tightly secure a child
restraint by way of an independent child restraint anchorage system
provides consumers with confidence in child restraint safety and has
the most potential for the highest, most effective, use of child
restraints.
III. Summary of the NPRM
a. What NHTSA Proposed To Address the Issue; Preference for Flexible
Latchplate Anchorage System Over the Rigid Bar Anchorage System
As a result of the usage and compatibility problems affecting the
installation of child restraint systems in vehicles, NHTSA proposed
that vehicles should be required to have a standardized system for
attaching child restraints that was independent of the vehicle belts.
On February 20, 1997, NHTSA published an NPRM proposing to require
vehicles to have an independent ``child restraint anchorage system''
installed in two rear designated seating positions (in vehicles with
two or more rear seating position) and to require child restraints to
be equipped with a means of attaching to that system (62 FR
7858).8
---------------------------------------------------------------------------
\8\ The NPRM was preceded by intensive agency efforts to develop
and establish requirements for universal child restraint anchorage
systems. For example, the agency held a public workshop in October
1996 to--
Assess and discuss the relative merits, based on
safety, cost, public acceptance and other factors, of various
competing solutions to the problems associated with improving the
compatibility between child restraint systems and vehicle seating
positions and belt systems, increasing child restraint
effectiveness, and increasing child restraint usage rates;
Assess the prospects for the adoption in this country
and elsewhere of a single regulatory solution or at least compatible
regulatory solutions; and
Promote the convergence of those solutions. See NPRM,
62 FR at 7860.
---------------------------------------------------------------------------
A ``child restraint anchorage system'' was defined to consist of
two lower child restraint anchorages at the seat bight and a tether
anchorage for attaching a top tether strap of a child restraint system.
The lower anchorages could consist of either flexible latchplates or
rigid bar anchorages. However, NHTSA considered the flexible latchplate
anchorage system to have cost and weight advantages over the rigid bar
anchorage system, so the agency favored the flexible latchplate
anchorage system by (1) requiring all child restraints to have buckles
for the flexible latchplates and by (2) requiring each vehicle having
rigid bar anchorages to provide adapters that could accommodate child
restraints with the buckles for the flexible latchplates. At the time
of the NPRM, Canada was also undertaking rulemaking to require user-
ready tether anchorages and NHTSA sought to harmonize with those
prospective requirements. (Canada has since adopted its proposal for
the tether anchorages. See, section V.d., infra.) The agency's NPRM
also proposed reducing allowable head excursion limits in the Federal
safety standard regulating child restraint systems, Standard 213, which
would have had the effect of requiring most, if not all child
restraints to be equipped with an upper tether strap.
The NPRM proposed requirements to specify the construction of the
child restraint anchorage system, the location of the anchorages, and
the geometry of related components, such as the hardware that attaches
to a child seat. To prevent the vehicle anchorages from failing in a
crash, the anchorages, including structural components of the assembly,
would have had to withstand specified loads in a static pull test.
NHTSA proposed applying the requirement for the flexible latchplate
system to all passenger cars, and all trucks, buses and multipurpose
passenger vehicles (MPVs) with a gross vehicle weight rating (GVWR) of
4,536 kg (10,000 lb) or less. Each vehicle would have had to have at
least two flexible latchplate anchorage systems rearward of the front
seat. If a vehicle had no rear seat or had insufficient space to
accommodate a rear facing infant seat, and were equipped with an air
bag cutoff switch, as original equipment (OE), that deactivates the air
bag for the front passenger position, one anchorage system would have
had to be provided in that position, and another in a rear seating
position to accommodate a forward-facing child restraint. A built-in
child seat could have been substituted for one of the systems, but not
both, since rear-facing built-in systems are currently unavailable. If
there were no switch to turn off the front passenger air bag,
installation of an independent anchorage system would not have been
permitted in the front passenger seat.
b. Proposed Leadtime
NHTSA believed that the user-ready tether anchorage requirement for
vehicles could be made effective at a much earlier date than a
requirement for the lower anchorages of the child restraint anchorage
system. This was, in part, due to the fact that vehicles already had a
tether anchorage structure (e.g., a reinforced hole) at rear seating
positions to satisfy current Canadian requirements. The NPRM proposed
that the tether anchorage requirement become effective September 1,
1999 for passenger cars and a year later for LTVs. These effective
dates were the same ones proposed by Canada for its user-ready tether
anchorage requirement. The NPRM proposed that the effective date for
reducing Standard 213's head excursion requirement, thereby requiring a
tether for most child restraints, would be September 1, 1999.
The agency sought comments on whether a phase-in requirement for
the lower anchorages in vehicles would be appropriate, and how long a
period is needed for full implementation of the requirement. Comments
were also requested on the appropriateness of phasing-in the
requirement that child restraints be equipped with the devices that
connect to the vehicle child restraint anchorage system.
[[Page 10792]]
c. NPRM's Estimated Benefits and Costs of the Rulemaking
The NPRM discussed the agency's tentative conclusions about the
impacts (e.g., costs and benefits) of a final rule. The annual benefits
of the rule were estimated to be 24 to 32 lives saved, and 2,187 to
3,615 injuries prevented.
The NPRM estimated the average cost of a rule requiring the
flexible latchplate anchorage system would be approximately $160
million. The cost of the rule for vehicles was estimated to be about
$105 million. The cost of the rule related to the vehicle would range,
per vehicle, from $3.88 (one flexible latchplate anchorage system in
front seat only) to $7.76 (for one flexible latchplate anchorage system
in front seat and one in back seat or two flexible latchplate systems
in rear seats). NHTSA estimated that 15 million vehicles would be
affected annually: 9 million passenger cars and light trucks with
``adequate'' rear seats, 3 million vehicles with no rear seat, and 3
million vehicles that can only accommodate a forward-facing child seat
in the rear seat (not a rear-facing infant seat). The cost of the
buckle attachments on the child seat was estimated to be about $55
million (3.9 million child restraints (excluding belt-positioning
boosters) at $14 per seat.) The rigid bar anchorage system was thought
to increase the cost of a child restraint by possibly $100, assuming
that the child restraint had to have rigid attachments and a heavy
structure to support those attachments.
d. Alternatives Considered
The agency considered and tentatively rejected several alternatives
to an independent child restraint anchorage system. Efforts to improve
compatibility of child restraint systems and vehicle interior designs
first focused on the extent to which vehicle seats and seat belt
systems could better perform their dual functions of attaching child
restraints and protecting adults, teenagers and older children. The
agency evaluated what the industry had developed by way of design tools
that would help optimize protection for both the restrained child and
older population groups.
The Society of Automotive Engineers' (SAE) Recommended Practice SAE
J1819, ``Securing Child Restraint Systems in Motor Vehicle Rear
Seats,'' specifies guidelines that vehicle and child restraint
manufacturers can use for designing their products with compatibility
in mind. The recommended practice specifies a common reference tool, a
``Child Restraint System Accommodation Fixture,'' that both vehicle
manufacturers and child restraint manufacturers can use in assessing
compatibility. In addition, J1819 provides design values to vehicle
manufacturers for certain characteristics of rear seats and seat belts,
such as seat cushion shape and stiffness, and seat belt anchorage
location, belt length, buckle and latchplate size, and lockability.
Likewise, J1819 provides design guidelines to child seat manufacturers
for child seat features that correspond to the vehicle features.
NHTSA believed that requiring compliance with J1819 alone would not
sufficiently improve compatibility. Most, if not all vehicle and child
restraint manufacturers already use J1819 when designing their
products. Requiring compliance with J1819 also seemed excessively
design restrictive for both vehicle and child restraint manufacturers.
It would perpetuate the difficulties vehicle manufacturers have in
designing their belts for the dual function of protecting both the
child restraint occupant and the adult.
Another approach that NHTSA had taken to improve compatibility was
to improve the belt system to specifically require a feature to improve
the belt's usefulness with a child restraint system. For vehicles
produced beginning in September 1995, NHTSA added a ``lockability''
requirement to the occupant crash protection standard (Standard 208).
The rule requires the lap belt to be lockable to tightly secure child
safety seats, without the need to attach a locking clip or any other
device to the vehicle's seat belt webbing (58 FR 52922, October 13,
1993).
While the lockability requirement ostensibly makes a locking clip
obsolete, it still depends on the user knowing enough and making the
effort to manipulate the belt system.9 Also, the vehicle
belt must be routed correctly through the child restraint, which may
not be an easy task in all cases. Further, the lockability requirement
does not address the effects of forward-mounted seat belt anchorages on
child restraint effectiveness.
---------------------------------------------------------------------------
\9\ A typical lockability device is the seat belt retractor that
can be converted from an emergency locking retractor (which locks
only in response to the rapid deceleration of the vehicle or rapid
spooling out of the seat belt webbing from the retractor) to an
automatic locking retractor by slowly pulling all of the webbing out
of the retractor and then letting the retractor wind the webbing
back up.
---------------------------------------------------------------------------
It became apparent that what was needed was for the vehicle system
that secured the child restraint system to be independent of the
vehicle system that restrained and protected the adult, teenager and
older child. This idea originated in Europe where work on a child
restraint anchorage system quickly evolved, most notably in the
technical committee of the International Organization for
Standardization (ISO).
Cosco, a child restraint system manufacturer, suggested an
independent child restraint anchorage system that is midway between
using the vehicle's belts to attach a child restraint and the child
restraint anchorage system developed by groups such as the ISO and
adopted today by this final rule. Cosco's ``car seat only'' (CSO)
system, consists of an independent lap belt that is installed in
vehicle seats separately from the integrated lap/shoulder belts
provided for adult passengers. Similar to other child restraint
anchorage systems such as the ISO rigid bar system or GM's flexible
latchplate system, the CSO is independent of the vehicle's current belt
system. Yet, the CSO still uses the design concepts associated with a
belt system, e.g., using a belt to wrap through or around the child
restraint to latch it into the vehicle. To Cosco, that is the appeal of
its system. Cosco believes that the CSO system would not require any
changes in the design and manufacture of child restraints and thus
would add no increase to the price of child restraints.
To NHTSA, the fact that the CSO system is essentially no different
from the historic lap belt means the dissatisfaction many consumers
have about the difficulty of attaching a child restraint is likely to
be perpetuated with the CSO. NHTSA was concerned that the CSO system
might not make attaching a child seat significantly easier than it is
today. To NHTSA, a new means of attaching child restraints had to be
explored. Commenters responding to the NPRM agreed.
IV. Summary of the Comments
NHTSA received over 70 comments in response to the rulemaking
proposal.10 Because the international community is
considering adoption of a standard for a universal, independent child
restraint anchorage system, the agency received submissions from
foreign governments as well as domestic entities. All commenters agreed
with the need for a universal, independent child restraint anchorage
system and overwhelmingly concurred with the proposed requirements for
a top tether anchorage. However, over half opposed the agency's choice
of the flexible latchplate
[[Page 10793]]
system over the rigid bar anchorage system for the lower anchorage
points.
---------------------------------------------------------------------------
\10\ Comments and other materials relating to the NPRM were
submitted to Docket No. 96-095, Notice 03, and Docket NHTSA-1998-
3390.
---------------------------------------------------------------------------
a. Commenters Supporting Flexible Latchplate Anchorage System
The tentative choice of the flexible latchplate system was
supported by the Michigan Department of State Police, the Automotive
Occupant Restraints Council, General Motors (GM), Advocates for Highway
and Auto Safety (Advocates), Indiana Mills and Manufacturing Inc.
(IMMI), the Drivers' Appeal for National Awareness (DANA), Gerry Baby
Products, and Evenflo Company.11 (Gerry and Evenflo have
since consolidated into one child restraint system manufacturing
company.) Several members of Congress sent a letter supporting the
flexible latchplate system.12
---------------------------------------------------------------------------
\11\ It should be noted that GM and IMMI were instrumental in
developing the flexible latchplate system. Century, Evenflo, Gerry
and Kolcraft are members of the Juvenile Products Manufacturers
Association (JPMA), which joined with GM, IMMI and other
manufacturers in petitioning NHTSA to adopt the UCRA system.
\12\ The letter, dated May 21, 1997, from U.S. Representatives
Constance A. Morella, Steny H. Hoyer, George R. Nethercutt, Jr.,
Julia Carson and Martin Frost, stated that the flexible latchplate
system ``would require no structural changes to new vehicles, and *
* * is easy-to-use, employing buckle and latch-plate technology that
is familiar to most consumers.'' Comment number 43 in Docket 96-95-
N03.
---------------------------------------------------------------------------
Proponents of the flexible latchplate anchorage system agreed with
the agency's tentative conclusions in the NPRM that the flexible
latchplate system appeared to be superior to the rigid bar anchorage
system because a child restraint equipped with buckles to attach to the
flexible latchplates would be less costly, bulky and heavy than a child
restraint equipped with rigid attachments. Some commenters supported
the flexible latchplate system because they believed that it needs a
shorter leadtime for implementation. IMMI, which helped develop the
flexible latchplate and buckle, believed that the appeal of its buckle
is that it provides a simple, intuitive, easy to use, and familiar
hardware concept which will give consumers ``a true sense of security
and familiarity that will translate into more [child] seats being used
as well as installed correctly.''
Some of the proponents of the flexible latchplate system objected
to the rigid bar anchorage system. Based on its belief that there is no
buckle that can latch to a round bar, and therefore that such a buckle
would have to be developed, IMMI suggested that the rigid bar anchorage
alternative would take three to five times as long to implement. IMMI
was also concerned that, under the specifications now under
consideration by the ISO working committee developing the draft
standard for the rigid bar system, the 6 mm bar would be permitted to
be located up to 70 mm (2.75 inches) rearward of the seat bight. The
commenter believed that locating the bars 70 mm from the seat bight
would seriously jeopardize their visibility and/or accessibility. A
letter ``strongly opposing the round bar interface'' was submitted by
Century Products, Gerry Baby Products, Evenflo Company, Kolcraft
Enterprises, and IMMI.13 The manufacturers stated that the
rigid bar anchorage system is unacceptable, arguing that the--
---------------------------------------------------------------------------
\13\ Century and Kolcraft have since informed NHTSA that with
certain qualifications, they have decided to favor the rigid bar
anchorage system over the UCRA. See section V.a, infra.
Rigidly mounted bars would not be visible or accessible inviting
misuse or non-use of car seats. No specifications or technology
exists for attachment connections to the round bar, and there is no
guarantee that these connectors could be available in three to five
---------------------------------------------------------------------------
years or be cost effective.
They were also ``concerned for the long term liability and risk
associated with use and performance on rigid systems designed to be
used with the 6 mm bar.''
b. Commenters Supporting Rigid Bar Anchorage System
The agency's proposal for making the flexible latchplate system the
preferred system was opposed by the United Nations Economic Commission
of Europe Group of Rapporteurs for Passive Safety (GRSP), the UK
Parliamentary Advisory Council for Transport Safety, the UK Department
of Transport, Transport Canada, the New South Wales Roads and Traffic
Authority (Australia), Ford Motor Company, Chrysler Corporation, BMW of
North America, Mercedes-Benz of North America, Volvo Cars of North
America, Insurance Institute for Highway Safety (IIHS), Kathleen Weber
of the University of Michigan Child Passenger Protection Research
Program (UMCPP), Volkswagen of America, Fisher-Price, Britax Romer, the
Millenium Development Corporation, Transport Research Laboratory Ltd.
(TRL), Safe Ride News, SafetyBeltSafe, and the University of Kansas
Medical Center. The commenters disagreed with the agency's tentative
conclusions in the NPRM that the rigid bar anchorage system will be
more costly and will add more weight and bulk to child restraints than
the flexible latchplate system, and will likely need a longer leadtime
to implement. They believed the rigid bar anchorage system and the
flexible latchplate system will have similar cost, weight and leadtime
impacts when the components that attach to the rigid bars are attached
to a child restraint by webbing (some call this type of attachment a
``non-rigid attachment,'' versus a rigid attachment). The commenters
further believed that the rigid bar anchorage system is superior
because it allows for more design flexibility in what child restraint
manufacturers can use to connect their child restraints to the rigid
bars; has greater potential safety benefits (for child restraints
equipped with rigid attachments) by reducing head excursion in side
impacts and by eliminating the need for the parent to tighten belts;
and enhances international harmonization of safety standards.
Several commenters stated that the agency's preference for the
flexible latchplate system was based on faulty premises, such as the
suggestion that hardware interfacing with the rigid bars will not be
available in the near future (commenters identified tether hooks as an
available, low-cost hardware); and that consumers are more familiar
with buckles and latchplates than with an rigid bar anchorage
connector. BMW stated that because both the flexible latchplate and
rigid bar anchorage systems permit the use of non-rigid attachments on
child restraint systems, BMW said there is no cost penalty associated
with the latter. The commenter stated that buckles for both the
latchplate and the rigid bar interfaces will have virtually the same
cost in production quantities. Also, BMW believed that the rigid bar
anchorage system could be implemented virtually as quickly as the
flexible latchplate design, and within the same leadtime. The Insurance
Institute for Highway Safety (IIHS) believed that buckles designed to
attach to the rigid bars may cost as little as $1.10 and can be
designed and produced in less than one year. As for vehicle costs, VW
believed that the rigid bar anchorage system would be less expensive
for vehicle manufacturers than the flexible latchplate system. (VW
cited NHTSA's October 17, 1996 cost analysis which estimated vehicle
costs for the flexible latchplate system to be $11.62, and for the
rigid bar system, $7.55.)
Several commenters believed an area where the rigid bar anchorage
system is superior to the flexible latchplate system is with regard to
the design flexibility of the systems. Kathleen Weber stated that ``The
[UCRA] flat plate, which can only be manifested in a soft-supported,
protruding configuration, is a short term expedient that offers little
opportunity for future
[[Page 10794]]
design improvement.'' Similarly, BMW believed that the flexible
latchplate system--
effectively freezes the current CRS technology * * *. [T]he U.S.
public will be forced to endure a system that does not have the
flexibility to provide both low cost child restraint systems (with
soft attachments) and advanced child restraints with enhanced side
impact protection and self-tensioning devices.
Many commenters, including Ford, Volvo, IIHS, the Roads and Traffic
Authority (RTA) of New South Wales (Australia) and others, believed
that the rigid bar anchorage system is superior to the flexible
latchplate system with respect to safety. Ford Motor Company believed
that the rigid bar anchorage system would increase child restraint
safety over the flexible latchplate system, particularly in side impact
crashes, at nearly equivalent cost for child restraint and vehicle
manufacturers. RTA stated that, while there is very little difference
in frontal crash protection provided by child restraints attached by a
flexible latchplate system and by the rigid bar anchorage system,
``[t]he real differences show up when you conduct side impact tests.
The rigid CANFIX/CAUSFIX 14 system appears to offer
considerable improved performance over the UCRA system and the current
Australian attachment system [lap belt and tether].'' The Department of
Transport in the United Kingdom stated that ``[w]e fully support the
adoption of rigid [6 mm diameter bar] anchorages believing that they
will simplify the fitting of CRS, significantly reduce the misuse of
CRS, and offer improved dynamic safety performance.'' The commenter
expressed concern that the flexible latchplate and the rigid bar are
not compatible with respect to their interfaces and that the flexible
latchplate system ``does not offer the possibility of a transition to
the rigid bar anchorage and the performance advantages it [the rigid
bar system] offers.''
---------------------------------------------------------------------------
\14\ CANFIX and CAUSFIX are the terms that Canada and Australia,
respectively, use in referring to a rigid bar anchorage system with
a tether anchorage. It is the system NHTSA is adopting today in this
final rule. (Footnote added.)
---------------------------------------------------------------------------
Several commenters also believed that the rigid bar anchorage
system would enhance child restraint safety in areas other than side
impacts, as well. Safe Ride News stated that a rigid bar anchorage
system using rigid attachments on the child restraint would minimize
misuse by permitting a simple, one-click installation that virtually
eliminates adjustment problems. Similarly, IIHS believed that the rigid
system (for both vehicle and child restraint system) has the advantage
of not requiring parents to tighten any belts. ``Failure to tighten
belts sufficiently is a common mistake parents make when using the
current child restraint systems * * *.''
Some commenters expressed concerns about potential safety problems
with the flexible latchplate system. In commenting in support of the
rigid bar anchorage system, Transport Research Laboratory Ltd. (TRL)
stated that ``A rigid attachment system [on both the vehicle and the
child restraint] offers significant advantages over the soft systems in
terms of ease of use and reduction in misuse. A soft attachment system,
such as that proposed, while giving good performance when well
tightened, will not give good performance when used as user trials
suggest they will be used.'' (The commenter did not elaborate on this
issue.) Volvo expressed a concern that ``the compressive forces and
bending moments resulting from both handling of the CRS and a crash
situation may give rise to excessive stresses and strains in the
[flexible latchplate]. This is less likely with the round ISOFIX
15 attachments.'' (The commenter did not elaborate on this
issue.) Volvo also stated that ``[i]n a test Volvo has performed using
the UCRA attachment there have been incidents of unintentional
unlatching of the latchplate due to the release button on the
latchplate being too close to the adjust seat belt buckle.'' The
commenter also stated that the UCRA latchplates may not be accessible
for foldable seats after folding and unfolding the seat backs and seat
cushions. IIHS also stated that ``using similar technology [to
conventional seat belt buckles, as with the UCRA system] is not
necessarily advantageous. In user trials, some consumers attempted to
use the conventional seat belt latches to attach child seats rather
than the designated child restraint latches in vehicles * * *.''
---------------------------------------------------------------------------
\15\ ISOFIX was the name originally used by the ISO working
group to describe its rigid bar anchorage system. The ISOFIX design
has evolved through the years from a 4-point rigid anchorage concept
to a 2-point design. The commenter presumably is referring to the
current 2-point anchorage system. For a discussion of the design
evolution of ISOFIX, see NHTSA's February 1997 Preliminary Economic
Assessment (which is entry 1 in Docket No. 96-95-N3).
---------------------------------------------------------------------------
Almost all of the commenters supporting the rigid bar anchorage
system argued that adopting that system would further international
harmonization of safety standards while adopting the flexible
latchplate anchorage system would not. The GRSP of the United Nations
Economic Commission for Europe stated that all of the governmental
representatives expressing a view on the NPRM supported a move to two
point rigid lower attachments. The GRSP stated that ``* * * NHTSA
should not encourage a unique national approach in its final
proposals.'' Ms. Kathleen Weber, chairperson of the U.S. delegation to
the ISO Working Group developing the draft ISO standard, stated:
It is clear that the European vehicle industry will move quickly
to recessed rigid bars for its [lower vehicle anchorages for child
restraints], U.S. manufacturers with world platforms will do the
same, and such anchors will probably be required in non-US markets
within a few years. By requiring the flat plate anchor in the U.S.
market, NHTSA will penalize consumers with an extra cost burden and
will isolate its child restraint market from the rest of the world.
Similarly, Transport Canada believed that the preferred system
worldwide is the rigid bar anchorage system, and thus expressed a
concern that the proposal's preference for the flexible latchplate
system does not provide for worldwide harmonization.
V. Summary of Post-Comment Period Events and Docket Submissions
a. ISO Working Group Refines and Completes Draft ISO Standard on Rigid
Bar Anchorage System
Since the NPRM, ISO Working Group 1 (WG 1) finalized its working
documents on the location of the rigid bar anchorages and the test
procedure for evaluating them. In the June 1998 meeting in Windsor,
Canada, the draft of the Canadian rule concerning requirements for top
tether anchorages (see section d, below) was incorporated into WG 1
activities to serve as the basis for the preparation of an ISO document
(ISO/WD13216-2) to be part of the ISO standard. The draft ISO standard
will be circulated to the ISO member bodies for voting. To be adopted
as an ISO standard, it has to be approved by at least 75 percent of the
member bodies casting a vote. NHTSA understands that the full committee
will vote on the draft international standard in early 1999.
B. Child Restraint Manufacturers Shift Support to Rigid Bar Anchorage
System
In June 1998, the agency received letters from child restraint
manufacturers Kolcraft, Cosco and Century expressing qualified support
for the rigid bar anchorage system. These manufacturers had originally
responded to the NPRM strongly opposed to that system but changed their
minds apparently after realizing that the rigid
[[Page 10795]]
bracket connector would not be required for the child restraint system.
These manufacturers stated that they now prefer the rigid bar
anchorage system over the flexible latchplate system,16
provided that the access and location of the anchorages allows design
flexibility for either a frame mounted (bracket-based) or a flexible
(strap) mounted connector on the child restraint. Factors cited for the
change in preference were performance, future child restraint system
design flexibility and international harmonization. Century said,
however, that the bars have to be accessible and visible. Cosco
believed that the cost effectiveness of the rigid bar anchorage system
and flexible latchplate system would be approximately equal, and that
``any differences in the using public concerning ease of use and/or
desirability of one with respect to the other would soon disappear if
such a real difference exists at all today.'' Cosco stated that the
rigid bar anchorage system
\16\ Cosco continues to favor the CSO system above all,
believing it to be the most cost-effective and quickest to
implement.
---------------------------------------------------------------------------
would help to eliminate certain types of force vectors which may
occur within the system of flat latchplates that could be
detrimental. It also clearly distinguishes the car seat attachment
system from any other hardware that may be near by.
c. Industry Conducts Consumer Focus Group Testing on Which Lower
Anchorage System Is Preferred
In April 1998, the American Automobile Manufacturers Association
(AAMA) and the Association of International Automobile Manufacturers
(AIAM) asked MORPACE International, Inc., to conduct a consumer clinic
to determine which of several methods of attaching child restraints
consumers in the U.S. find most acceptable. Century 1500 STE Prestige
convertible restraints were used as the representative child restraint.
The baseline method of attaching the Century seat was the vehicle belt
system. This was compared against a flexible latchplate system (with
the buckles attached to the child restraint by straps) and a rigid bar
anchorage system (with hooks and other connectors attached to the child
restraint by straps or by a rigid bracket attachment), and variations
of these attachments. A Volkswagen Passat sedan was fitted with a
flexible latchplate system and with the rigid bar anchorage system.
The clinic participants were 254 people who were the principal
drivers of their vehicle and who care for children 4 years of age or
less. Each participant was asked to install the child restraints and
then asked about his or her interest in the restraint. Later, the
participants were informed of the prices for the restraints and were
asked again about their interest in each restraint. The prices MORPACE
gave for the baseline child restraint was $63, the child restraint
equipped with buckles for the flexible latchplate system was $78, the
child restraint with the rigid bracket attachment for the rigid bar
system was $128, the rigid bar anchorage strap-based restraint with a
snap hook was $73, and the rigid bar anchorage strap-based system with
a buckle-type connector to a 6 mm bar was $80.
The following is the percentage of the participants who were very/
somewhat interested in the restraints before and after they were
informed of the prices. UCRA (78/77 percent); rigid bar anchorage
restraint with a buckle attached to it by webbing (67/57 percent);
rigid bar anchorage restraint with rigid bracket-based attachment (64/
45 percent); and rigid bar strap-based system with snap hook (64/45
percent). After the prices were provided, the UCRA restraint was most
preferred (39 percent), followed by the rigid bar anchorage restraint
with rigid bracket-based attachment (19 percent), the rigid bar strap-
based system with snap hook (15 percent), and the rigid bar anchorage
restraint with a buckle attached to it by webbing (14 percent). The
study stated that the reason behind the bracket-based rigid bar
anchorage option's being rated second instead of first is its higher
price and weight. Restraints equipped with variations of these UCRA and
rigid bar anchorage connectors also received support, as did the
baseline restraint, albeit in smaller percentages. MORPACE prepared a
final report on the clinic and its findings, which the agency placed in
docket NHTSA-1998-3390.
Following the issuance of the report, a number of motor vehicle and
child restraint manufacturers wrote to NHTSA concerning the findings.
Copies of these letters have been placed in docket 3390. GM and Indiana
Mills Manufacturing Inc. (IMMI) stated that they believed that the
clinic showed that consumers' preferences are highly in favor of the
flexible latchplate system. GM and IIMI stressed that the clinic showed
that consumers are willing to pay the added cost of the flexible
latchplate system for added security and performance, but that
consumers will not accept the cost and weight of a bracket-based rigid
bar anchorage child restraint.
Some manufacturers did not agree that the clinic necessarily showed
a preference for the flexible latchplate system. BMW, Volvo,
Volkswagen, Mercedes-Benz, Toyota, Fisher-Price and the University of
Michigan Child Passenger Protection Research Program believed that the
clinic showed that child restraint systems interfacing with the rigid
bars had a combined first choice preference of 48 percent, compared to
a 40 percent first choice preference for the flat latchplate. Chrysler
did not believe it was appropriate to add the proportions of
participants who expressed preferences for the rigid bar anchorage
variants and to express that sum as a preference for the round bar
anchorage. However, Chrysler believed that the clinic's findings are
limited in that they reflect consumer views on the ``ease of use'' of a
child restraint but not consumer preference for the vehicle anchorages
used. Chrysler also reiterated its belief, expressed in earlier
comments to the docket, that the rigid bar anchorage system has greater
potential safety benefits than the flexible latchplate system.
Ford believed that while it may not be statistically valid to add
the percentages of respondents favoring child restraints that attach to
the rigid bar anchorages, it would be ``directionally right, in that
the [rigid bar anchorages] are more flexible [design-wise] and can be
used with a wider variety of child restraints.'' Ford believed that the
clinic found that consumers want (1) an alternative way of attaching
child restraints, and (2) more than anything, a child restraint that
provides safety and security. Ford reiterated its belief that the rigid
bar anchorage system is the best vehicle system. Ford said the system
provides consumers with a wider variety of child restraints, and is the
most immobile, a feature that MORPACE has said signifies to consumers
that the seat is secure, which MORPACE says was ``the most important
criterion'' for the respondents in evaluating a child restraint.
Century Products stated that it believed that the high preference
rating for child restraints designed for the flexible latchplate system
is due to the familiarity of the latchplates. The company stated that
``the three designs using the 6 mm rigid bars in the vehicle also
showed acceptance by the respondents indicating that the 6 mm bar is
acceptable to users.''
A number of these commenters also said that the prototype child
restraints used in the clinic were of highly inconsistent quality. For
example, some believed that the rigid bar anchorage bracket-based
restraint was not representative because it was unrealistically heavy,
high, and upright,
[[Page 10796]]
in order to adapt the unmodified production Century restraint to a
rigid bar anchorage base. It was 3.6 kg (8 lb) heavier than the UCRA
restraint. They stated that, in contrast, the flexible latchplate
restraint and others did not include the weight of any of the
reinforcements that are needed for the restraint to meet Standard 213's
dynamic test and thus were lighter than would be an actual restraint.
They also believed that the vehicle's flexible latchplates used in the
clinic were substantially more sophisticated than what the agency had
proposed and thus far more costly. Chrysler also said that the $128
price given for the rigid bar anchorage bracket-based child restraint
was too high, because costs would be lowered if the bracket mechanism
were produced in high volume.
d. Canada Issues Rule on Tether Anchorages
In September 1998, Canada adopted its final rule amending its
tether anchorage requirement in section 210.1 of the Canadian Motor
Vehicle Safety Regulations. As a result of an effort to harmonize
internationally on tether anchorage requirements, NHTSA's proposal on
tether anchorages reflected almost all of the provisions that had been
proposed by Canada (March 15, 1997) prior to its final rule.
Since 1989, Canada had required that tether anchorages be installed
on all passenger cars. However, that requirement did not require tether
anchorages to be ``user-ready,'' i.e., it did not require the
installation of the hardware necessary for the attachment of the tether
strap. Consumers could not use the tether anchorage on the vehicle as
delivered from the factory. While Canada required that manufacturers
provide a pre-drilled hole in a reinforced location specifically
designed for the installation of the hardware, it did not require that
such hardware be installed. Consequently, parents typically had to take
their vehicle to a dealer or repair shop to have the hardware
installed. Canada's new rule requires the factory installation of user-
ready tether anchorages for all anchorages in passenger cars
manufactured on or after September 1, 1999, and a year later in all
minivans and light trucks.
The Canadian rule requires a specified number of tether anchorages,
depending on vehicle type and the number of rows or seating positions
in the vehicle. Generally, it requires passenger cars and minivans to
have two or three anchorages. The rule specifies the zone in which a
tether anchorages must be located for a particular seating position. It
specifies strength requirements, and a method for testing the strength
of the anchorages.
The rule contains a number of changes to the test procedure that
Canada had proposed for testing the strength of the anchorages. The
proposal would have specified testing the anchorages by attaching a
strap to the anchorage and passing that strap forward over the seat
back. In response to comments and discussions with manufacturers,
Canada changed the test method to specify the use of one of two
prescribed static force application test devices. Both represent a
child restraint system with a tether. One device replicates a child
restraint that attaches to a rigid bar anchorage system. This device
will be used to test the tether anchorage in a seating position that
has the rigid bar anchorage system. The other represents a child
restraint that is attached by the vehicle's belt system, and is used to
test a tether anchorage at a position that is not equipped with a rigid
bar anchorage system. The test is conducted by installing the test
device on the seat using the seat belt or the rigid bars, as
appropriate, attaching the tether strap to the tether anchorage, and
applying a test force to the child restraint device, rather than
directly to the tether anchorage.
VI. Agency Decision Regarding Final Rule
a. Summary of the Final Rule
This final rule requires motor vehicle manufacturers to install
child restraint anchorage systems, consisting of lower rigid bar
anchorages and a user-ready upper tether anchorage, in their vehicles.
The 6 mm round bars in the vehicle seat must be rigidly mounted. Thus,
they may not be attached to the vehicle by webbing material. This rule
also requires child restraints to be permanently equipped with a means
of being attached to the lower vehicle anchorages. It does not,
however, specify either the design of the means of attachment or how
that means is permanently attached to the child restraint.
This rule requires vehicles to have two child restraint anchorage
systems at two rear designated seating positions, if the vehicle has at
least two rear seating positions. This rule also requires vehicles with
three or more rear designated seating positions to have a user-ready
upper tether anchorage at a third rear seating position.17
It amends the child restraint standard by reducing the limits on
allowable head excursion. The agency expects that in order to comply
with the reduced limits, most forward-facing child restraint models
will be equipped with an upper tether strap. When used, a tether
reduces head excursion and the likelihood of head impacts against the
vehicle structure.
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\17\ If a vehicle has a rear seat with insufficient space to
accommodate a rear facing infant seat, and is equipped with an OE
air bag cutoff switch that deactivates the air bag for the front
passenger position, one anchorage system must be provided in that
position, and another in a rear seating position to accommodate a
forward-facing child restraint. If a vehicle has no rear seat, and
is equipped with an OE air bag cutoff switch that deactivates the
air bag for the front passenger position, one anchorage system must
be provided in that position.
---------------------------------------------------------------------------
To provide consumers with the rigid bar anchorage system as quickly
as possible, this rule will start a three-year phase-in of the
requirements for the rigid bars, beginning September 1, 2000. The bars
will ultimately be required in all passenger cars, and in trucks and
multipurpose passenger vehicles with a gross vehicle weight rating
(GVWR) of 3,856 kg (8,500 lb) or less, and in buses (including school
buses) with a GVWR of 4,536 kg (10,000 lb) or less. There will be a
two-year phase-in of the user-ready tether anchorage for passenger cars
beginning September 1, 1999. The user-ready tether anchorage will be
required in the other vehicle types 18 beginning September
1, 2000.
---------------------------------------------------------------------------
\18\ Because of practicability concerns, convertibles and school
buses are excluded from the tether anchorage requirements.
---------------------------------------------------------------------------
Child restraints will be required to have the components for
attaching to the rigid bars beginning September 1, 2002. The restraints
will be dynamically tested under Standard 213 when attached by those
components to rigid bars on the standard seat assembly specified in the
standard. They will be tested both with and without attaching a tether.
Child restraints will have to meet a reduced head excursion limit
beginning September 1, 1999. A tether will probably be needed to meet
this requirement, and one may be attached for the test. Child
restraints will also have to meet the standard's existing head
excursion limit when tested attached by a lap belt and nothing else, to
ensure that head excursion is limited if the tether is not used.
The estimated average cost of this rule is approximately $152
million annually. The cost of the rule for vehicles is estimated to be
about $85 million. The costs of the rule related to the vehicle will
range, per vehicle, from $2.82 (one rigid bar anchorage system in front
seat
[[Page 10797]]
only) to $6.62 (for a system in front seat and one in back seat or two
systems in rear seats, plus a tether anchorage). NHTSA estimates that
15 million vehicles will be affected annually: 9 million passenger cars
and light trucks with ``adequate'' rear seats, 3 million vehicles with
no rear seat, and 3 million vehicles that can only accommodate a
forward-facing child restraints in the rear seat (not a rear-facing
infant seat). The impact of the rule on child restraint systems is
estimated at $67 million (3.9 million child restraints at $17.19 per
restraint, based on webbing-attached connectors). The cost per child
restraint system varies depending on the type of connector used, e.g.,
a hook versus a buckle, and the means used to attach the connector to
the child restraint system, e.g., webbing versus a rigid attachment.
The annual benefits of the rule are estimated to be 36 to 50 lives
saved, and 1,231 to 2,929 injuries prevented.
b. Summary of Key Differences Between NPRM and Final Rule
The main difference between the final rule and the NPRM concerns
the lower anchorage portion of the child restraint anchorage system in
vehicles. Instead of permitting a choice between lower anchorages of
either the flexible latchplate system or the rigid bar system, the
final rule mandates the latter system. The NPRM would have allowed
vehicle manufacturers the option of installing the rigid bar system
only if they provided an adapter, such as a connector (that need not
have been permanently attached to the vehicle) that would have had a
component on one end that latches onto the rigid bar, and a latchplate
on the other, for attaching to buckles on a child restraint that is
designed for a flexible latchplate anchorage system. Commenters
overwhelmingly opposed an adapter, believing that the adapter would be
lost or misused by consumers. On reevaluating this issue, NHTSA agrees
that mandating a single system would better ensure that the child
restraint anchorage system is universal to all vehicles, for all child
restraints, and for all consumers regardless of the type of vehicle or
child restraint they may be using for a particular trip.
Second, this final rule requires vehicle manufacturers to rigidly-
mount the 6 mm bars. Thus, it does not permit the bars to be attached
to the vehicle by webbing, as had been proposed. The purpose of
requiring rigid mounting is to maintain better control over the
compatibility between child restraints and the anchorage system.
However, connectors on the child restraint are permitted either to be
attached by webbing, or to be rigidly mounted.
Other differences between this final rule and the NPRM relate to
provisions concerning: the types of vehicles and of child restraints
that are subject to the requirements; the number of anchorage systems
that are required in each vehicle; the visibility and placement of the
rigid bars in the vehicle; a requirement for an audible or visual
indicator that the child restraint is securely attached to the bars;
the strength requirements and test procedures for testing the child
restraint anchorage system and the tether anchorage; and leadtime for
and a phase-in of the requirements.
VII. Issue-by-Issue Discussion of the Agency Decision on Content of
Final Rule
a. NHTSA Determines the Anchorage Systems Are Essentially Equal on the
Merits
The agency initially gave preference to the flexible latchplate
anchorage system over the rigid bar anchorage system after weighing the
abilities of each system to accomplish the goals that the agency
believed a uniform attachment system should meet. 62 FR at 7867-7868.
NHTSA believed that an anchorage system should:
--Improve the compatibility between child restraint systems and vehicle
seats and belt systems, thereby decreasing the potential that a child
restraint was improperly installed;
--Ensure an adequate level of protection during crashes;
--Ensure correct child restraint system use by ensuring that the child
restraint systems are convenient to install and use, and will be
accepted by consumers;
--Ensure that the child restraint systems and anchorages are cost
effective and available within a reasonable leadtime; and,
--Achieve international compatibility of child restraint performance
requirements for uniform anchorage points.
NHTSA tentatively concluded that the flexible latchplate system
would, on balance, best achieve these goals. The agency stated that the
rigid bar anchorage system and flexible latchplate anchorage system
appeared comparable in terms of safety performance and public
acceptance, but the flexible latchplate anchorage system appeared to
have advantages over the others with respect to its cost impact, and
near-term availability. The agency further stated that the flexible
latchplate anchorage system had advantages in terms of its usability
and visibility. The agency believed the familiarity of the components
(particularly the crucial connector pieces--buckles and latchplates--
that attach a child restraint to the vehicle system) was a definite
advantage over the other systems. Also, the agency believed that child
restraints designed for use with the flexible latchplate system were
not as bulky or heavy as child restraints designed for use with the
rigid bar anchorage system, which would increase the public acceptance
of the flexible latchplate system.
The agency's proposal to give preference for the flexible
latchplate system over the rigid bar anchorage system for the lower
anchorages was supported by some commenters, but opposed by most
commenters in their comments on the NPRM or in their post-comment
period submissions. Proponents of the flexible latchplate anchorage
system agreed with the agency's tentative conclusions in the NPRM that
the system appeared to be superior to the rigid bar system because a
child restraint made for the flexible latchplate anchorage system would
be less costly, bulky and heavy than a child restraint designed to
attach to a rigid bar anchorage system. Some commenters supported the
flexible latchplate anchorage system because they believed that a rule
based on that system could be implemented more quickly. Some believed
that the flexible latchplate system was preferable because its buckle
is simple, intuitive, and familiar to consumers. GM argued that the
AAMA/AIAM 1998 consumer clinic proved that consumers overwhelmingly
prefer the flexible latchplate anchorage system because of its superior
installation accuracy and acceptable costs, compared to alternative
concepts, including the rigid bar anchorage system.
Opponents of the flexible latchplate anchorage system disagreed
with those views. They believed the rigid bar anchorage system and the
flexible latchplate anchorage system would have similar cost, weight
and leadtime impacts. They stated that the agency's tentative decision
to give preference to the flexible latchplate anchorage system was
based on faulty premises, such as believing that the hardware
interfacing with the rigid bars would necessarily be costly and
unavailable in the near-term. These parties strongly disputed that the
1998 consumer clinic showed the flexible latchplate anchorage system
had greater public acceptance. In fact, many believed the clinic showed
a public preference for systems using the rigid bar anchorage system in
the vehicle,
[[Page 10798]]
because most of the respondents chose, as their first choice,
variations of child restraints that had attachments that were designed
to attach to the rigid bar anchorage system. (Forty-eight percent chose
child restraints designed to attach to the rigid bars, compared to 39
percent that chose child restraints designed for the flexible
latchplate system.)
After reviewing the comments and other new information before it,
NHTSA concluded it needed to revise its assessment of the relative
merits of the flexible latchplate system and the rigid bar anchorage
system. The agency's main reason for proposing to give preference to
the flexible latchplate system over the rigid bar anchorage system was
information indicating that the installation of rigid bar anchorage
systems in motor vehicles would make it necessary for child restraints
to be equipped with the following three features: two rigid prongs, or
brackets; a heavy supporting structure for those prongs or brackets;
and specialized jaw-like clamps to attach to the rigid lower anchorages
on the vehicle. This information consisted of statements by the
supporters of the rigid bar anchorage system describing the child
restraints and of the prototypes or mock-ups they had provided prior to
the NPRM. Those prototypes or mock-ups included all three of these
features. The addition of these features to child restraints would have
had a substantial cost impact on child restraints (essentially doubling
the price of a child restraint), and added substantially to its bulk
and weight. The agency also believed that manufacturers would need
substantial time to design child restraints with the brackets and
supporting structure. Further, NHTSA was concerned that consumers would
not be familiar with the new technology.
All commenters supporting the rigid bar anchorage system told the
agency that the brackets were not necessary to attach a child restraint
to the rigid bar anchorage system. Commenters, including many child
restraint manufacturers, said that a simple hook, made to attach to a
rigid bar, could and would be used by many child restraint
manufacturers if the rigid bar anchorage system were adopted. The hook
could be attached to the child restraint by means of webbing, identical
to the attaching of the buckle on a child restraint designed for the
flexible latchplate system. After the NPRM was published, some child
restraint manufacturers developed prototype child restraints, equipped
with hooks, to demonstrate to NHTSA the feasibility of using hooks as
the connector hardware and of using webbing for attaching hooks to a
child restraint. Further, almost all of the child restraint
manufacturers asserted that, if allowed, they would use straps to
attach the connector to the child restraint. These assertions
apparently reflected their judgment that the use of straps would be
practicable and publicly acceptable.
These new prototypes, reinforced by the new assertions of the child
restraint manufacturers, changed NHTSA's assessment of the relative
advantages of the flexible latchplate and rigid bar anchorage systems.
The emergence of straps as a viable means of attaching the connector
made it necessary for the agency to reverse its earlier tentative
conclusion that a child restraint must have the heavy brackets to
attach to a rigid bar anchorage system, and its derivative tentative
conclusions about related advantages of the flexible latchplate system
concerning the cost, bulk, and weight of child restraints designed for
the system.
NHTSA's cost estimates in the NPRM were based on the information
indicating that the brackets had to be used on the child restraint
system. The high cost of a rigid bar anchorage child restraint,
relative to a flexible latchplate child restraint, was mostly due to
the material then believed by the agency to be needed for the bracket
structure and not to the cost of the hardware connecting to the 6 mm
bar. Several commenters stated that buckles designed to attach to 6 mm
bars would, as production volume rose, ultimately be comparable to, if
not less than, the cost of the buckle of the flexible latchplate
system. NHTSA agrees with these statements because the types of
components (spring, latch, release button and casing) of current
prototype buckles designed to attach to a rigid bar and to the flexible
latchplate, are basically the same. Because the same types of
components are used in both buckles, it is reasonable to conclude that
the cost under similar production assumptions are likely to be similar.
Thus, there would be no significant cost difference between a child
restraint designed for the rigid bar anchorage system that uses webbing
to attach the connector to the restraint and a child restraint designed
for the flexible latchplate system. Accordingly, the agency now
concludes there need not be a cost advantage to the flexible latchplate
system compared to the rigid bar anchorage system.
NHTSA also believes that child restraints designed for the rigid
bar anchorage system would be comparable in weight and bulk to child
restraints designed for the flexible latchplate anchorage system if
they used webbing to attach the connector to the child restraint. The
incremental bulk and weight of a rigid bar anchorage child restraint,
relative to a flexible latchplate child restraint, was due to the
material then believed by the agency to be needed for the bracket
structure and not to the hardware connecting to the rigid bar.
Accordingly, there need not be an advantage to the flexible latchplate
anchorage system over the rigid bar anchorage system in terms of the
bulk and weight of the child restraints.
b. There Is Substantial Consumer Interest in Both Anchorage Systems
Supporters of the flexible latchplate anchorage system argue that
the AAMA/AIAM consumer clinic shows that consumers prefer their system
and that for this reason, the flexible latchplate system should
prevail. NHTSA's view of the clinic results is discussed in Appendix B.
In brief, the agency cannot conclude that the results clearly warrant
the agency's selection of either the flexible latchplate system or a
rigid bar anchorage system. The agency recognizes that consumers gave
their highest scores to the flexible latchplate design used in the
clinic. However, combining the results of the child restraints designed
for the rigid bar anchorage system accounted for an even larger number
of participants. Further, NHTSA believes that the high score of the
flexible latchplate design was at least partially due to the fact that
consumers are currently more familiar--and perhaps more comfortable--
with the buckle and latchplate design. The agency believes further that
once the rigid bar anchorage system and child restraints with the new
connectors are introduced, the public will become equally familiar and
comfortable with those new designs. Moreover, the agency anticipates
that consumers will be receptive to the design flexibility of the rigid
bar anchorage system. As discussed below in section d.2., the anchorage
system allows them to choose from a variety of connector hardware
designs and child restraint systems to satisfy their needs.
c. NHTSA Determines Only One Lower Anchorage System Can Be Selected
The NPRM would have allowed vehicle manufacturers the option of
installing the rigid bar anchorage system if they provided an adapter
(that need not be integral to the vehicle) that would enable a child
restraint that is designed for the flexible latchplate system to be
used with the rigid bars. The adapter would have to latch at one end
onto the rigid bar and at the other end onto the flexible latchplate
system buckle. Commenters overwhelmingly
[[Page 10799]]
opposed the concept of an adapter, believing that adapters would be
lost or misused by consumers. For example, Toyota Motor Corporation
stated that an adapter--
will further complicate the tightening procedure and therefore
securing the CRS will be more difficult. Accordingly, we believe
that there will be an increased possibility of misuse, resulting in
loose fit and/or improper securing of the CRS to the vehicle. In
addition, we believe this will add to the owner's confusion as to
how to properly affix this system. * * * In addition, Toyota is
concerned as to whether the owner of these vehicles will take the
necessary precautions to keep from losing the adapter(s), as any
additional loose articles in a vehicle are more likely to be
misplaced or lost.
After reviewing the comments, the agency concludes that mandating a
single type of anchorage system would ensure that motorists will find
the same child restraint anchorage system in all vehicles and that the
system will be compatible with all child restraints, regardless of the
make or model of vehicle or child restraint they may be using for a
particular trip. Allowing use of an adapter might not only perpetuate
existing child restraint compatibility problems, but also exacerbate
them beyond what they are today. Thus, the agency decided it must
choose one, and only one, system to require.19
---------------------------------------------------------------------------
\19\ In the NPRM, the agency discussed its tentative conclusion
that J1819 and FMVSS No. 208's lockability requirement were
insufficient as alternative solutions to an independent child
restraint anchorage system. The agency did not receive any comments
opposing this. The agency also tentatively rejected Cosco's CSO
system as an alternative to the proposed child restraint anchorage
system. Cosco commented in disagreement with the agency. NHTSA's
final decision declining to use the CSO system is explained in
Appendix A to this final rule.
---------------------------------------------------------------------------
d. NHTSA Selects the Rigid Bar Anchorage System Based on Its Advantages
Over the Flexible Latchplate Anchorage System
1. The First Advantage Is Harmonization of Standards
NHTSA's selection of the rigid bar anchorage system advances its
international harmonization policy goal of identifying and adopting
those non-US safety requirements that reflect equivalent or higher
levels of safety performance than the counterpart U.S. standard.
Requiring the rigid bar system will enhance the safety of child
restraints by making them easier to install and possibly more securely
installed than by means of the vehicle's belt system. Further,
harmonizing the U.S. standard permits vehicle and child restraint
manufacturers to have a greater measure of planning certainty and
predictability in designing and selling their products, helps ensure
that parents are provided an anchorage system that meets their safety
needs at the lowest possible cost, and facilitates the global marketing
of child restraints.
NHTSA's selection of the rigid bar anchorage system also accords
with its statutory obligations. The Trade Agreements Act of 1979, as
amended (July 26, 1979, P.L. 96-39, Sec. 1(a), 93 Stat. 144.) (19
U.S.C. Sec. 2501 et seq.), requires Federal agencies to take into
consideration international standards and, if appropriate, base the
agencies' standards on international standards. In addition, the
National Technology Transfer and Advancement Act of 1995 (P.L. 104-113)
requires all Federal agencies to use technical standards ``that are
developed or adopted by voluntary consensus standards bodies, using
such technical standards as a means to carry out policy objectives or
activities determined by the agencies and departments.''
The rigid bar anchorage system is the one most likely to be chosen
as a harmonized design under the auspices of the United Nations
Economic Commission for Europe (UN/ECE).20 The rigid bar
anchorage system is supported by the expert group within WP.29 that
considers issues relating to child restraints and vehicles, the Group
of Rapporteurs for Passive Safety (GRSP). At the 23rd session of the
GRSP meeting of experts in June 1998, the GRSP accepted a proposal for
requiring rigid bar anchorages. At the 24th session of the GRSP meeting
of experts in December 1998, the GRSP formed an informal group to look
into developing a proposal to be presented at the May 1999 GRSP
meeting. The proposal is to consist of alternative means, including a
top tether, to reduce the possibility of undesirable rotation that
might otherwise occur when a child restraint is attached to some
vehicle seats by means of the two lower rigid bar anchorages only. The
GRSP plans to discuss the proposal during the May 1999 meeting and
expects to decide during its December 1999 meeting whether to adopt a
means to address the concern of possible undesirable rotation and, if
so, which means should be adopted.
---------------------------------------------------------------------------
\20\ The UN/ECE Working Party on the Construction of Vehicles
(WP.29) administers an agreement, known as the 1958 Agreement,
concerning the adoption of uniform technical prescriptions for
wheeled vehicles, equipment and parts and develops motor vehicle
safety regulations for application primarily in Europe. (While U.S.
officials actively participate in WP.29 and thus participate in the
development of standards, the United States is not a Contracting
Party to the 1958 Agreement. Thus, it cannot vote on whether a
regulation is to be adopted by the Contracting Parties.) Various
expert groups within WP.29 make recommendations to WP.29 as to
whether regulations should be adopted as ECE regulations. WP.29 in
turn makes recommendation to the Contracting Parties to the 1958
Agreement. It is ultimately the Contracting Parties that vote on
whether a recommended regulation is to be adopted under the
Agreement as an ECE regulation.
---------------------------------------------------------------------------
The rigid bar anchorage system is also favored in other
international forums as well. The rigid bar anchorage system, with a
top tether anchorage, is the system preferred by Canada and Australia
and is the child restraint anchorage system most likely to be adopted
by those countries. Both of these countries already require a user-
ready tether anchorage for attaching child restraints.
The International Standards Organization (ISO) also appears to be
moving toward adoption of the rigid bar system. The ISO working group
that has been developing the rigid bar anchorage system is completing
its working documents on the system and is preparing to circulate the
draft standard to the ISO member bodies for voting. The ISO working
group circulated a committee draft report for voting. The ballots
received by the deadline of May 4, 1998 showed that no country
disagreed to circulate a draft of the international standard to the ISO
Central Secretariat for ballot. (The U.S. abstained from voting because
agreement has not been reached within the U.S. domestic auto industry
on the use of rigid versus flexible anchorages.) NHTSA understands that
the full committee will vote on the draft international standard in the
near future. To be adopted as an ISO standard, the draft has to be
approved by at least 75 percent of the member bodies casing a vote.
2. The Second Advantage Is Enhanced Design Flexibility Which Provides a
Reasonably Predictable Prospect for Design Improvements That Will
Enhance Either Safety or Public Acceptability or Both
The rigid bar anchorage system encourages design flexibility to a
greater extent than the flexible latchplate anchorage system. The rigid
bar anchorage system has the advantage of allowing child restraint
manufacturers flexibility in developing a variety of possible
connectors to the bars. Unlike the flexible latchplate system, which
envisions a specific design of a buckle to connect to the latchplate,
the rigid bar anchorage system gives child restraint manufacturers
maximum leeway in
[[Page 10800]]
designing connectors.21 For example, child restraint
manufacturers may use designs ranging from jaw-like clamps to buckles
to simple hooks, and may attach these to the child restraint using
means ranging from brackets to webbing. A number of child restraint
manufacturers support the rigid bar system because of its design
flexibility.
---------------------------------------------------------------------------
\21\ Some opponents of the rigid bar anchorage system were
concerned that Britax may hold a patent on a specific ``jaw'' type
of connector and could restrict the free use and development of the
connector by other manufacturers. In communications between Britax
and NHTSA, Britax has repeatedly stated that it does not hold a
patent on the connector. The agency has reviewed copies of patents
5,524,965, 5,487,588 and 5,466,044 which Britax submitted to NHTSA,
and agrees with Britax that it did not have a patent on the
connector itself. (The patents were for various designs of child
restraints that had the jaw connector.) In further response to a
request by NHTSA, by letter dated August 10, 1998, Britax informed
the agency that it has filed a Terminal Disclaimer to waive all
patent rights to ISOFIX connectors described in patents 5,524,965,
5,487,588 and 5,466,044. A copy of this letter has been placed in
the docket. The effect of Britax's action is to dedicate these
patents to the public, thus waiving any patent protections it may
have for these patents. This puts to rest the concerns that were
raised about Britax possibly restricting the free use of development
of the connector.
---------------------------------------------------------------------------
The design flexibility of the rigid bar system also has
implications for potential improvements in the safety provided by child
restraints. For example, Century Products has indicated that the rigid
bar system could enable them to design booster seats (a type of child
restraint system, see 49 CFR 571.213, S4) for children over 18 kg (40
lb) that could better limit head excursion than present boosters. A
rigid attachment on the booster restraint might reduce some of the
excessive forward motion that a child restraint attached to the vehicle
seat by a belt experiences when tested with a 6-year-old dummy, due to
elongation of the belts.
Consumers would also benefit from design flexibility, in that they
could choose from a variety of child restraint systems to purchase to
suit their needs or tastes. For some, a one-step ``plug-in'' design,
such as that seen on Britax prototypes with rigid connectors, might be
the most convenient or desirable, while others may prefer a child
restraint that has a connector attached by webbing because such a
system would weigh and cost less than restraints that have rigid
connectors.
3. The Third Advantage Is Possible Safety Benefits
The NPRM stated that both the flexible latchplate anchorage system
and the rigid bar anchorage system have performed satisfactorily in
dynamic tests, which implied that both would provide comparable levels
of safety. Supporters of the rigid bar anchorage system disagreed with
the agency, suggesting that that system has the potential to better
protect children with regard to two aspects of safety.
The first safety aspect concerns the relative performance of the
systems in side impacts. Michael Griffiths and Paul Kelly of the Roads
and Traffic Authority (RTA), New South Wales, Australia, submitted data
on side impact sled tests RTA conducted comparing the performance of
the CAUSFIX system (CAUSFIX is the rigid bar anchorage system with a
tether anchorage, which is the system NHTSA is adopting in this final
rule, see footnote 13, supra), the flexible latchplate system, and a
lap belt plus tether system. (``Comparative Side Impact Testing of
Child Restraint Anchorage Systems,'' Kelly, Roads and Traffic
Authority, New South Wales, Special Report 96/100, March 1997.) The
side impact tests were conducted in accordance with Australian Standard
(AS) 3691.1, except for the addition of a simulated door structure,
replicating a rear door of a large sedan, adjacent to the test seat.
Testing was conducted with the test seat mounted at both 90 degrees and
45 degrees to the direction of sled travel. The lower anchorage points
for the CAUSFIX were positioned 280 mm (11 inches) apart on the test
seat structure, with the inboard anchorage approximately 610 mm (24
inches) from the inner surface of the door. An instrumented 9-month-old
dummy was used in all the tests.
RTA found that, for forward-facing seats,22 only the
CAUSFIX was able to prevent contact between either the dummy's head or
the child restraint and the door structure in the 90 degree test. RTA
stated that head contact with the door was evident in the test
involving the flexible latchplate system.
---------------------------------------------------------------------------
\22\ The rear-facing seats were tethered. Because today's rule
does not require rear-facing infant seats to have a tether, this
discusses only the tests of the forward-facing seats.
This appeared to be largely the result of the restraint rotating
towards the door at the end of its sideways movement. As a
consequence, the dummy's head moved forward relative to the CRS
[child restraint system] and contacted the front portion of the
side-wing. In turn, the side-wing deflected and allowed the head to
roll around its front edge, as the CRS rebounded from the door * *
*. In contrast, the CAUSFIX system did not allow rotation * * *. The
CAUSFIX concept offered better head protection compared to the
---------------------------------------------------------------------------
conventional seat belt/top tether systems.
(Id., page 5.)
Many of the supporters of the rigid bar anchorage system included
comments on their belief that side impact benefits could be attained
with the system. In contrast, GM stated in its comment (pp. 10-11):
It has been alleged that the proposed combination of UCRA
anchorages and a strap-based CRS may not provide adequate protection
in a high severity lateral impact. However, no field accident
statistics have been provided to support an allegation that high
speed lateral impact performance should be a primary area of concern
in the U.S. In fact, data analyzed by NHTSA researchers demonstrate
that the primary child safety issue is the non-use of CRSs. A
secondary concern is misuse of the CRS. Misuse includes failing to
properly fasten the CRS's internal harness system or improperly
securing the CRS in the vehicle.
While various groups continue to develop proposals for lateral
impact test protocols and related dummy and injury assessment
techniques, it appears unlikely that consensus on these topics will
be reached for years. The continued debate should not delay
implementation of improved CRSs and UCRA systems. This is
particularly true since it is not apparent that the current U.S.
field situation demonstrates a need for a side impact crash
evaluation protocol. Further, it has not been established that
lateral dummy head excursion is a meaningful predictor of injury in
side impacts. Even if it were, NHTSA tests have shown that the
existence of a top tether reduces lateral head excursion by one
third compared to a current CRS secured without a top tether * * *.
NHTSA has evaluated these and all other comments on this issue and
concludes that the agency cannot make a precise determination of the
relative side impact benefits based on the information available thus
far. The RTA's test data were few in number. Further, the real world
relevance of the 90 degree test is unclear at this point. NHTSA does
not know if the path of a child's head in a 90 degree impact will
necessarily be lateral. The path will depend on a variety of factors,
including the speed of the struck vehicle, and the point of impact to
the struck vehicle (forward part, middle, rear part). Further, NHTSA
cannot determine at this time whether reduced head excursions would
necessarily reduce injuries and fatalities in side impacts. Crash data
should be analyzed to determine answers to these issues. The agency has
been working with the ISO working group on the development of a side
impact test procedure. NHTSA will be taking part in an evaluation of
the side impact test protocols in the future. For now, however, the
agency cannot conclude that the rigid bar anchorage system is more
advantageous than the flexible latchplate system in side impacts.
The second aspect of safety on which proponents of the rigid bar
anchorage system commented was that the combination of rigid lower
anchorages
[[Page 10801]]
on both vehicles and child restraints would virtually guarantee that
the child restraint would be snugly attached to the vehicle seat.
Commenters stated that studies and informal clinics have shown that
consumers regularly fail to properly tighten the belt used to install
child restraints. With a rigid bar anchorage system on both the vehicle
and the child restraint, the child restraint is secured automatically
once the consumer properly attaches the two rigid points of the seat,
so there is no need for a separate tightening action by the consumer.
Conversely, GM stated that concerns about parents not tensioning the
flexible latchplate belts are unfounded, based on the findings of GM's
consumer preference clinic (GM did not elaborate on those findings).
A number of consumer advocates urged NHTSA to adopt the rigid bar
anchorage system because they have witnessed that parents often do not
adequately tighten the vehicle belt attaching the child restraint to
the vehicle. A child restraint with rigid attachments designed to
attach to rigid bar anchorages in the vehicle would eradicate the
problem of excessive slack in the belts.23 By adopting the
rigid bar anchorage system, this final rule provides consumers the
rigid bar anchorage system in the vehicle and provides them the
opportunity to purchase a child restraint with the rigid attachments if
they want the more convenient system.
---------------------------------------------------------------------------
\23\ Some commenters suggested that NHTSA require automatic
retractors on child restraints that use webbing to attach the
connector, such as child restraints using webbing to attach the
connector to the rigid bar. NHTSA estimates that the consumer cost
of a retractor would be $2.50 to $3 per retractor, or $5 to $6 per
child restraint. To minimize the cost impacts of this rule, NHTSA
has decided not to require automatic retractors on child restraints.
---------------------------------------------------------------------------
e. NHTSA's Final Rule Is Not Identical to the Draft ISO Standard
This final rule adopts most of the requirements under consideration
by the ISO, adopts some that are not part of the ISO draft standard,
and adopts some requirements that are dissimilar to those under
consideration by the ISO. These are discussed below. Other differences
with the draft ISO standard are discussed throughout this section
(VII).
4. Bars May Not Be Attached to the Vehicle by Webbing Materials
The NPRM proposed to permit vehicle manufacturers to install
``semi-rigid'' anchorages in vehicles for the child restraint anchorage
system. Semi-rigid bar anchorages refers to 6 mm bars that are attached
by non-rigid material (webbing), extending from the vehicle seat bight.
Semi-rigid bar anchorages basically look like the anchorages of the
flexible latchplate system, except with a 6 mm round bar attached to
the end of the webbing instead of a latchplate. The term ``semi-rigid
anchorages'' is from the draft ISO standard (ISO/22/12/WG1, June 1998,
Annex A), which permits vehicle manufacturers the option of installing
semi-rigid bar anchorages as an interim alternative to the anchorages
that are rigidly held in place. The draft ISO standard permits the use
of semi-rigid bar anchorages for a limited period of time as an interim
measure to address the concerns that had been expressed by some U.S.
vehicle and child restraint manufacturers toward rigid bar anchorages.
NHTSA's proposal allowed semi-rigid anchorages to harmonize to the
extent possible with the version of the prospective ISO standard.
After reevaluating this issue, NHTSA has decided to require vehicle
manufacturers to rigidly mount the 6 mm bars. Thus, bars may not be
attached to the vehicle by webbing, as had been proposed. The agency
made this decision to maintain better control over the compatibility
between child restraints and the anchorage system. Requiring one type
of attachment system on the vehicle (i.e., requiring the 6 mm bars to
be rigidly mounted) better standardizes the vehicle anchorage system,
which reduces the potential for confusion on the part of parents (who
might be confused if they are looking for or expecting one type of
anchorage system and come across another), and the misuse that
typically results from confusion.24 To determine whether a
bar is ``rigidly'' mounted to the vehicle, this final rule specifies
that the bar must be attached to the vehicle such that it will not
deform (e.g., elongate, move, or deflect) when subjected to a 100
Newton (N) force in any direction. To further standardize the system,
this final rule limits the length of the bars to not less than 25 mm,
but not more than 40 mm. The upper limit is to reduce the likelihood
that the bars may bend in a crash.
---------------------------------------------------------------------------
\24\ Connectors on the child restraint are permitted to be
attached by webbing, or they may be rigidly mounted. Design
flexibility in attaching the connector to the child restraint
enables child restraint manufacturers to better tailor their
products to meet consumer demand, and reduces the cost impact on
consumers purchasing child restraints.
---------------------------------------------------------------------------
Even if NHTSA had decided to give vehicle manufacturers the option
of installing non-rigidly mounted bars, it appears that they would not
take advantage of that opportunity. Vehicle manufacturers supporting
the rigid bar anchorage system did not indicate in their comments or
other submissions that they would install non-rigid bar anchorages.
NHTSA believes most, if not all, want to install the rigid bar
anchorages. They emphasized what they believe to be superior side
impact performance attributed to the rigid bar anchorage system, which
can only be attained by use of a rigid system. They liked the fact that
the rigid bar anchorage system did not give the appearance of
``clutter'' on vehicle seats from sets of child restraint anchorage
belts and latchplates. Further, it appears that the provision for semi-
rigid anchorages was included in the ISO draft standard to address what
the working group believed was a desire to use such anchorages in this
country. The Group of Experts on Passive Safety of the ECE stated in
commenting on the NPRM that ``[t]here is no benefit in Europe opting
for a semi-rigid system as an interim step.'' NHTSA understands this to
mean that European manufacturers are not interested in installing semi-
rigid anchorages as an interim step prior to the installation of rigid
anchorages.
2. The Bars Must Be Visible or the Vehicle Seat Back Marked To Assist
Consumers in Locating Them
While NHTSA has departed from its proposal in order to harmonize
with revised location and visibility/marking requirements for rigidly-
mounted anchorage bars in the draft ISO standard, the agency has not
followed that draft standard in all respects. In the NPRM, the agency
proposed location requirements for rigidly-mounted 6 mm bar anchorages.
The location requirements were based on requirements developed in draft
by the ISO working group in ISO/WD13216-1i, November 15, 1996. The NPRM
proposed that the 6 mm diameter bars would be located using a child
restraint fixture whose configuration and dimensions replicate a child
restraint system. (The NPRM referred to the fixture as the ``child
restraint apparatus.'' For convenience, and in response to VW's
suggestion in its comment, this final rule uses the term ``child
restraint fixture'' (CRF), which is the term used in the draft ISO
standard.) The CRF would be placed on the vehicle seat cushion and
against the seat back. Anchorage bars that are rigidly attached were
proposed to be located 50 mm (about 2 inches) behind of the rearmost
lower corner surface of the fixture (called point Z). They also must
not be more than 120 mm from the H point of the seating position. (The
H point is the mechanically hinged hip point of a
[[Page 10802]]
manikin which simulates the actual pivot center of the human torso and
thigh. See definition, 49 CFR Sec. 571.3.)
In its June 1997 draft revision of the ISO standard, WG1 changed
the rearward location requirement to specify that rigidly mounted bars
shall be not more than 70 mm (2.7 in) behind point Z. (The limit on the
forward placement of the bars was not changed.) This specification is
reflected in the June 1998 draft standard. The distance for the fore-
aft placement of the bars was increased from 50 mm to 70 mm (2 to 2.7
in) to make allowances for extremely contoured rear seats in some types
of sport cars. Contoured seat cushions or seat backs in these vehicles
may make it difficult to place the bars within 50 mm (2 in) of the CRF
without having the bars be so far forward in the seat bight that they
interfere with the comfort or safety of adult occupants.
Some commenters (Century, Gerry Baby Products, IMMI, Evenflo, and
Cosco) were concerned about the visibility and accessibility of the
bars at the seat bight. Other commenters pointed out that the ISO
working group would be revising its draft standard and suggested that
NHTSA should reference the location requirements of the revised draft
standard.
After evaluating the comments, NHTSA has decided to adopt the
limits on the forward (not more than 120 mm from the H-point of the
seating position) and rearward (not more than 70 mm behind point Z)
placement of the bars in the current draft ISO standard. The agency has
determined that the 70 mm distance is needed to ensure that the bars
are rearward enough in vehicles with contoured cushions to limit
excessive head excursions for children in a crash 25 and to
avoid injuring the person occupying the vehicle seat in a crash or
interfering with his or her comfort during normal vehicle operation. At
the same time, the agency is mindful of the concerns of child restraint
manufacturers that the child restraint anchorage system must be visible
and accessible to be properly used.
---------------------------------------------------------------------------
\25\ For a discussion of the interaction of child restraints and
forward-mounted anchorages, see the NPRM, 62 FR at 7859, columns 1-
2.
---------------------------------------------------------------------------
NHTSA believes that most vehicles, except those with highly
contoured seats, will have the bars 50 to 60 mm (2 to 2.4 in) from the
CRF. At this distance, the agency believes that the bars would
generally be visible at the seat bight without compressing the seat
cushion or seat back.
The final rule requires that vehicles in which the bars are not
visible must have a permanent mark on the vehicle seat back at each
bar's location. The permanent mark required by this final rule is a
small 13 mm (\1/2\ inch) diameter circle in a color that contrasts with
the seat material and that is located above each individual anchorage,
to help users locate and use the bars. The mark will indicate the
presence of the anchorage system and act as a guide showing where to
engage the bars. Consumers may not otherwise learn of the existence of
a child restraint anchorage system in a particular vehicle or at a
particular seating position in a vehicle without some type of visual
reminder that the anchorage system is present. Even when they know the
bars are present, they may not know precisely where in the seat bight
to look for the bars. NHTSA notes if vehicle manufacturers do not want
to mark their seats for esthetic or cost reasons, they need not do so
if they install the bars such that there is an unobstructed view of the
bars at an angle of 30 degrees from a horizontal plane tangent to the
seat cushion.
This visibility requirement is significantly different from the one
that NHTSA proposed and somewhat different from the visibility
requirement in the draft ISO standard. In the NPRM, NHTSA proposed
that, for rigid bar anchorages, inter alia, at least one lower
anchorage bar shall be readily visible to the person installing a child
restraint. That proposal was based on the ISO draft version in
existence at the time. The ISO working group changed those requirements
in the June 1997 draft version to specify that, wherever possible, at
least one lower anchorage bar, one guidance fixture, or one seat
marking feature (significantly larger than the one specified in NHTSA's
final rule) shall be readily visible to the person installing the child
restraint. NHTSA has determined that the proposed visibility
requirement for the bars would have likely precluded vehicle
manufacturers from placing the bars at the maximum 70 mm distance from
the CRF, since at that distance the bars may not be visible. As stated
above, the bars may need to be placed at the maximum distance on
extremely contoured seats for the safety and comfort of adult
passengers seated in that seating position. Because of this, the agency
is not adopting its proposal that at least one of the bars has to be
visible.
The NPRM requested comments on whether the webbing attaching the
anchorage hardware on the child restraint should be color coded to
distinguish the webbing from the straps comprising the harness for the
child. A number of commenters supported color coding, while others did
not. The agency has decided not to require color coding of the
attachment system at this time. The Insurance Corporation of British
Columbia (ICBC) and IMMI report contrasting experiences with regard to
the propensity of clinic participants to confuse the webbing attaching
the buckles of the flexible latchplate system to the child restraint
with the webbing of the child restraint's internal harness. NHTSA notes
that intermixing appears to be far less likely with the rigid bar
system than with the flexible latchplate system because the types of
connectors used to attach to the rigid bars are not likely to look like
the buckles used for the child restraint harnesses.
3. A Tether Anchorage Is Not Required by the Draft ISO Standard, but Is
Required by This Final Rule
The NPRM proposed to require user-ready top tether anchorages in
vehicles. The draft ISO standard does not at this time include a
provision for tether anchorages. Some supporters of a rigid system on
both vehicles and child restraints believe that some restraints made to
attach to the vehicle by means of a rigid attachment can meet a more
stringent head excursion limit without a tether.
Test data show that an attached tether substantially improves the
ability of a child restraint to protect against head impacts in a
crash, when the child restraint is attached to the vehicle seat by the
belt system or by a flexible latchplate anchorage system. In the U.S.,
parents have not attached the tethers in vehicles that lack a user-
ready tether anchorage. However, Canada's experience indicates that
parents are more likely to attach the tethers when a user-ready tether
anchorage is factory-installed. Overall, commenters to the NPRM agreed
with the agency that consumer-ready tether anchorages in vehicles are
needed to increase the likelihood that consumers will attach a tether.
For these reasons, and because a large proportion of child restraints
will likely be attached to the child restraint anchorage system by
webbing material, NHTSA believes there is good reason to require a
user-ready tether anchorage in vehicles. The agency notes that the
requirement for a user-ready tether anchorage will harmonize with
Canadian requirements adopted in September 1998.
f. The Types of Vehicles That Are Subject to the Adopted Requirements
The NPRM proposed to apply the requirement for a child restraint
anchorage system to passenger cars, and
[[Page 10803]]
to trucks, multipurpose passenger vehicles and buses under 4,536 kg
(10,000 lb) gross vehicle weight rating (GVWR). The agency had
tentatively decided to include vehicles with a GVWR between 3,856 and
4,536 kg (8,500 and 10,000 lb) in an effort to ensure that such a child
restraint anchorage system would be available in vehicles used to
transport children to child care programs.
Commenters on the proposed applicability of the rule discussed
whether there was a need to apply the rule to all vehicles above 3,856
kg (8,500 lb) GVWR. The Automotive Occupant Restraints Council (AORC),
GM and Chrysler believed that the requirement should not apply to
vehicles above 3856 kg (8,500 lb) because most vehicles in the 3856 to
4536 kg (8,500 to 10,000 lb) category are for commercial applications
other than passenger transport. AORC said that if NHTSA wishes to apply
a rule to vehicles above 3,856 kg (8,500 lb) to regulate vehicles used
for child care programs, the agency should apply the rule to school
buses and not to all vehicles greater than 3,856 kg (8,500 lb).
The Mobile Teaching School Bus Project of Indiana University
commented that a final rule should also apply to large school buses
(over 4,536 kg (10,000 lb) GVWR) to address issues relating to the
transportation of infants, toddlers and preschoolers on school buses.
The American Academy of Pediatrics also said that all school buses
should be subject to the rule. In contrast, the Lake Cumberland Head
Start expressed concern that applying the rule to school buses would
``skyrocket the cost of a new bus'' and could have a very detrimental
effect on the Head Start program budget. The National Association of
State Directors of Pupil Transportation Services expressed concern
whether the agency would be justified in applying the rule to school
buses. Chrysler questioned whether the proposed rule would be
appropriate for school buses, believing that a requirement for only two
child restraint anchorage systems ``would hardly meet the needs of the
users.'' Chrysler said that anchorage systems could be specified as a
matter of contract on the part of individual school bus purchasers.
After reviewing the comments, NHTSA has decided to limit the
applicability of the rule to passenger cars and to MPVs and trucks with
a GVWR of 3,856 kg (8,500 lb) or less, and to buses (including school
buses) with a GVWR of 10,000 lb or less. The agency is not applying the
rule to other vehicles with a GVWR in the 3,856 to 4,536 kg (8,500 to
10,000 lb) range because most vehicles in that range typically do not
carry child restraints. The agency is not applying the rule to school
buses with a GVWR greater than 4,536 kg (10,000 lb) because this was
not proposed, and the agency has not had the benefit of full and
meaningful comment on this issue.
Buses with a GVWR of up to 4,536 kg (10,000 lb) are included in the
final rule because they are regularly used to transport children small
enough to be in child restraints. Chrysler believed that a requirement
that specifies only two child restraint anchorage systems on buses used
to transport children to child care programs would not meet the needs
of the care givers. NHTSA urges purchasers who anticipate that they
will be needing more than two child restraint systems in their vehicles
to order their vehicle with the additional child restraint anchorage
systems necessary to meet their needs. The agency has drafted this
final rule to apply the standard's configuration, location, strength
and marking requirements to any additional voluntarily-installed rigid
bar anchorage system installed on a new school bus, or on any other
vehicle. This is to ensure that children will be provided the same high
level of crash protection no matter which particular child restraint
anchorage system they may be using at the time of a crash. The
configuration, location, strength and marking requirements will apply
to any rigid bar anchorage system installed on a new vehicle beginning
September 1, 1999.
g. The Number of Anchorage Systems That Are Required in Each Vehicle
In the NPRM, the agency proposed to require a child restraint
anchorage system at each of two rear seating positions. The NPRM did
not specify which rear seating positions would have had to be equipped
with the anchorage systems. As a practical matter, manufacturers were
likely to install the anchorages in the two outboard positions because
the anchorages could best fit there in most passenger cars. It would be
difficult to fit anchorage systems side-by-side, e.g., in the center
rear seat and at an adjacent outboard seat in small vehicles. The
agency requested information from commenters on whether there is
information indicating a need for an anchorage system at more than two
positions, such as demographic data on the number of children who are
typically transported in child restraints in a family vehicle.
Many commenters addressed the issue of how many seating positions
should have a child restraint anchorage systems. Most of them
recommended that either all rear seating positions in cars should be so
equipped, or at least an additional (i.e., third) tether anchor should
be required. Presumably, as a practical matter, the additional tether
would be installed in the rear center position. A few commenters
submitted demographic data to support their position that more than two
anchorage systems are needed in vehicles. However, these data did not
show that there were a significant number of families with three or
more children in child restraints. To minimize the cost of this rule,
this rule adopts the proposal for two full child restraint anchorage
systems.
However, NHTSA is requiring that if a vehicle has at least three
designated seating positions in the rear seat or second and third row
of seats, another seating position, other than an outboard position,
shall be equipped with a user-ready tether anchorage. This requirement
addresses the concerns of many commenters that the center rear seating
position in cars would not have an improved means of attaching child
restraints, even though that is the position preferred by many adults
to place a restraint. In the typical family car with three rear seating
positions, the center rear seating position would thus have a tether
anchorage in addition to the lap belt (and in more and more cars, a lap
and shoulder (Type II) belt), to give consumers flexibility in where
they choose to restrain their children. NHTSA is not requiring that one
of the two independent anchorage systems be placed in the rear center
position in a vehicle having such a seating position because, as
explained above, it may be difficult to fit the lower anchorages of two
child restraint anchorage systems, or two child restraint systems,
adjacent to each other in the rear seat of small vehicles.26
The final rule also requires that, in vehicles with three or more rows
of seating positions, at least one child restraint anchorage system
must be at a seating position in the second row. Some parents may want
to place the child restraint in the second row rather than further back
in the vehicle to comfort or supervise the restrained child from a
closer distance. This requirement ensures that a child restraint
anchorage system will be available in the second row to such a parent.
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\26\ NHTSA is allowing manufacturers to install one built-in
child restraint system in lieu of one of the required tether
anchorages or one of the required child restraint anchorage systems.
A built-in child restraint system is a child restraint system that
is a permanent and integral part of the vehicle. See S4, 49 CFR
Sec. 571.213.
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[[Page 10804]]
To better ensure that a vehicle's designated seating position and
child restraint anchorage system on that seat will be able to fit a
child restraint, this final rule requires the vehicle to be designed
such that the CRF can be placed inside the vehicle and attached to the
lower anchorages of the child restraint anchorage system. If the CRF
cannot attach to the child restraint anchorage system, the vehicle
cannot be certified as meeting Standard 225, the standard adopted today
for child restraint anchorage systems. When testing for compliance with
this requirement, NHTSA will place adjustable seat backs in the
manufacturer's nominal design riding position in the manner specified
by the manufacturer. The nominal design riding position should be the
same position that the manufacturer recommends in its instructions to
parents. Adjustable seats will be adjusted to their full rearward and
full downward position.
This final rule requires that any tether anchorage or child
restraint anchorage system installed in a new vehicle must meet the
configuration, location and strength requirements of the standard. This
requirement applies to voluntarily-installed anchorages that are
installed in a new vehicle in addition to those required by the
standard. This is to better ensure that the anchorages will perform
adequately and that a child will be assured a requisite level of
performance no matter which tether anchorage or child restraint
anchorage system is used. These requirements will apply to any child
restraint anchorage installed on a new vehicle beginning September 1,
1999.
h. Lockability Requirement Will Be Retained Until 2012
The NPRM requested comment on whether the ``lockability''
requirement in S7.1.1.5 of Standard No. 208, ``Occupant Crash
Protection'' (49 CFR 571.208) should be deleted as unnecessary if
requirements for a child restraint anchorage system are adopted. The
agency wished to explore whether a lockability requirement may not be
needed for a seating position with a universal anchorage system since
the vehicle's belt would no longer be used to attach a child restraint
with attachment devices. On the other hand, the agency also recognized
that lockability might be needed to attach child restraints that are
not equipped with attaching devices, even if the vehicle seat has such
a system.
Graco, SafeRide News, AORC, GM, Indiana University, Advocates,
Ford, Chrysler and the Center for Auto Safety commented on this issue.
All of these commenters said that vehicle seats with a child restraint
anchorage system should still be subject to the lockability requirement
to meet the needs of parents using a child restraint that is not
equipped with attachment devices. GM and Ford suggested that
lockability could be deleted some time after all child restraints are
equipped for the child restraint anchorage system.
The agency agrees that the lockability requirement should be
retained until virtually all child restraint systems in use have the
attachments that connect the restraint to the child restraint anchorage
system. Until then, the vehicle belts should be lockable to use with a
child restraint that is not equipped with attachment devices. The
agency believes that, on average, child restraints are used not more
than 10 years. Under today's rule, all new child restraints will be
required to have attachments that connect to the child restraint
anchorage system beginning in 2002. Because child restraints last on
average about 10 years, by 2012, most child restraints in use will be
able to use the child restraint anchorage system and will not need
lockable belts. This rule rescinds the lockability requirement
beginning September 1, 2012. The requirement is rescinded on that date
for just those seating systems with a child restraint anchorage system,
and not for all seats.
GM and Ford also suggested that the lockability requirement be
deleted for the air bag equipped right front passenger seat, in light
of the NPRM's proposal to disallow a child restraint anchorage system
in that position in vehicles that lack an OE on-off switch for the air
bag. NHTSA has decided not to delete the requirement at this time.
Notwithstanding the efforts of the agency, industry, State and local
officials and safety advocates to urge parents to place children in the
rear seats, some parents may decide to place toddler seats in the front
passenger seat with an air bag, or with an air bag and an on-off
switch. In that situation, the lockability of the lap and shoulder
belts would help ensure that the belt holds the child restraint system
as tightly as possible against the seat back of the front seat, as far
away as feasible from the air bag and the relatively hard structure of
the dashboard. Lockable belts may be distinguished from a standardized,
independent anchorage system in that the presence of the latter
implies, more than a lockable belt whose lockability feature is not
obvious, that the seat is appropriate for a child restraint system.
This may not be the case if an air bag is present.
On September 18, 1998, NHTSA published an NPRM proposing to upgrade
the agency's occupant protection standard to require advanced air bags
(63 FR 49958). The agency proposed to add new requirements to prevent
air bags from seriously injuring children and other occupants. When the
final rule on that rulemaking is issued, NHTSA will possibly delete the
requirement in today's final rule that an independent child restraint
anchorage system must not be in the front seat of a vehicle that lacks
an OE on-off switch and the related requirement concerning the
lockability provision applying to that seating position. This issue
will be addressed at the appropriate time in the context of that
rulemaking.
i. Strength Requirements for Lower Rigid Bars of Child Restraint
Anchorage System and Compliance Test Procedures
In the NPRM, the agency proposed that each lower anchorage would be
tested separately by applying a force of 5,300 N (1,190 lb) to the
anchorage in the forward horizontal direction parallel to the vehicle's
longitudinal axis. The force would be applied by means of a belt strap
that is fitted at one end with hardware for applying the force and at
the other end with hardware for attaching to an anchorage or connector.
The agency proposed that the force would be applied so that the 5,300 N
(1,190 lb) force is attained within 30 seconds, with an onset rate not
exceeding 135,000 N (30,337 lb) per second, and would be maintained at
the 5,300 N (1,190 lb) level for at least 10 seconds. The NPRM would
have specified that when tested in this manner, no portion of any
component attaching to the lower anchorage bars shall move forward more
than 125 mm (5 inches), and that there shall be no complete separation
of any anchorage component. The test procedure and force levels were
based on suggestions from petitioners AAMA et al. on the flexible
latchplate anchorage system.
GM and Ford suggested that loading all three anchorages at one time
(the two lower anchorages and the top tether anchorage) is the most
appropriate method to evaluate in a static load test how a child
restraint will perform dynamically in limiting forward excursion. GM
recommended using a fixture, representing a child restraint, in the
static pull test. GM believed that use of the fixture more accurately
depicts how the child restraint will perform in a crash. The fixture
would be attached to the lower anchorages and to the top tether
anchorage, and pulled. Ford also recommended using a fixture that
[[Page 10805]]
represents the geometry of a child restraint system. Ford recommended
using the ISO draft test procedure, which uses a fixture called a
``Static Force Application Device (SFAD).'' Ford believed that the ISO
fixture applies forces on the anchorages that are higher than the
forces applied to the fixture, because it applies realistic vertical
forces in addition to the horizontal forces. Ford suggested applying
force to the test fixture at 10 degrees above the horizontal (as in
Standard No. 210, Seat Belt Anchorages, 49 CFR 571.210) to replicate
the effect of pre-impact braking and vehicle pitching during a crash.
NHTSA has evaluated the above comments regarding the proposed
procedure for testing the lower anchorage system. The agency agrees
with the commenters' suggestion that it should use a fixture for
testing the lower anchorages. The agency believes that the forces of a
crash are simultaneously applied to all anchorages and not to one
anchorage at a time. Because of this, it is the agency's belief that
using a fixture that represents a child restraint system better
simulates the conditions of a crash. However, the agency will not
attach a top tether anchorage when testing the lower anchorages. Not
attaching the tether anchorage is consistent with the draft test
procedure being developed by the ISO working group for the rigid bar
anchorage system. This is also consistent with the agency's objective
to ensure that the child restraint anchorage system will retain the
child restraint system in the event that the tether is misused or not
used at all.
This final rule adopts the SFAD test fixture specified in the draft
ISO standard for testing the strength of the rigid bars and adopts
aspects of the test procedure proposed in the NPRM. The SFAD engages
the vehicle's rigid bars with rigidly attached connectors replicating,
in placement and design, the connectors on a child restraint. The SFAD
is not connected to the tether anchorage. A reference point on the SFAD
(designated ``Point Y'' on the device) is used to determine compliance
with the strength requirements. When a test force is applied to the
rigid bars by pulling on the SFAD at a point that is approximately
midway from the top of the device, the child restraint anchorage system
shall not allow Point Y on this SFAD to be displaced more than 125 mm
(5 inches).27
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\27\ This final rule refers to the SFAD of the ISO draft
standard as ``SFAD 2.'' SFAD 2 is also used to test tether
anchorages at seating positions that are equipped with a full child
restraint anchorage system (i.e., with the rigid lower anchorage
bars and the tether anchorage). This final rule also refers to a
fixture, called ``SFAD 1'' in this rule, to test tether anchorages
at seating positions that do not have a full child restraint
anchorage system. SFAD 1 is attached by way of the tether anchorage
and the vehicle's seat belt system.
---------------------------------------------------------------------------
Several commenters addressed the adequacy of the force levels
proposed to be applied to the anchorages. The NPRM proposed to require
that a 5,300 N (1,191 lb) force be maintained for 10 seconds. Gerry
Baby Products asked whether the 5,300 N static load is sufficiently
high to ensure adequate performance in a crash. Gerry said it has
measured dynamic loads in excess of 5,300 N. Indiana Mills and
Manufacturing Inc (IMMI) also commented that the proposed force of
5,300 N is lower than what they experienced in dynamic testing. The
Roads and Traffic Authority (RTA) of New South Wales commented that in
designing tether anchorages, the Australian Design Rule requires that
the anchorages sustain a 3,400 N (764 lb) static load. It said,
however, that they record dynamic loads well above this in sled
testing.
NHTSA has determined that the strength requirements proposed in the
NPRM are generally high enough to ensure that the lower anchorage
system will be able to withstand the loads generated by a child in a
child restraint in a crash. This final rule specifies a forward load of
11,000 N, using a fixture that applies the load to both lower
anchorages simultaneously (and not to the tether
anchorage).28 The 11,000 N forward load is similar to the
10,600 N load that was proposed in the NPRM for testing the strength of
the lower anchorages (5,300 N applied to each lower anchorage).
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\28\ This rule also includes a lateral load of 5,000 N (1,124
lb). The 5,000 N is the lateral load specified in the draft ISO
standard.
---------------------------------------------------------------------------
The 11,000 N forward load requirement is supported by test data
conducted by Transport Canada. Canada performed 48.3 km/h (30 mph)
dynamic testing of a 6-year-old (48 lb) child dummy in a (17 lb)
booster restraint that was attached to the vehicle seat assembly by the
rigid lower bars of a child restraint anchorage system. Dynamic loads
recorded at one lower bar was approximately 5,500 N, resulting in a
combined dynamic load of about 11,000 N. There is a margin of safety
incorporated into the adopted strength requirement by way of the method
by which the 11,000 N static load is applied to the anchorages, which
is discussed below with regard to the static load onset and hold
periods.
As to why NHTSA believes test data on the 6-year-old (48 lb) dummy
are pertinent, child restraints are increasingly marketed for children
of older ages and higher weights. Recent statements by several child
restraint manufacturers indicate that some of their child restraint
systems are currently being offered for sale for children weighing up
to, and in some cases more than, 60 lb. (A copy of these statements has
been placed in NHTSA Docket 74-09 General Reference.) These restraint
systems are primarily belt-positioning boosters, which are a type of
child restraint booster seat regulated by Standard 213.
While belt-positioning boosters use the vehicle's lap and shoulder
belts (Type II belts) to restrain the child, many belt-positioning
boosters are also designed for dual use as a toddler restraint. (A
toddler restraint is a forward-facing child restraint system, generally
recommended for children weighing 30 to 40 lb, that has its own
internal harness to restrain the child, and is dependent on the
vehicle's anchorage system to connect the child restraint to the
vehicle seat. The harness is designed to be removed by the consumer
when the child restraint is to be used with a vehicle's Type II belt as
a belt-positioning booster.) Under today's final rule, toddler
restraints must be designed to attach to the rigid bar anchorage system
of the vehicle. Toddler restraints restraining children weighing up to
40 lb will impose the forces generated by these children on the rigid
bars. In addition, in a misuse case, where a parent restrains a child
weighing more than 40 lb in a booster that is in the toddler restraint
mode, the loads could be higher. There is also substantial interest,
which NHTSA shares, in the possibility of designing toddler restraints
to accommodate children heavier than 40 lb. One tethered child
restraint is currently sold in Canada for use by children with a
maximum weight of 48 lb, and this trend may occur in the U.S.
29 Given that a child restraint anchorage system would be
used with children with weights up to and possibly more than 40 lb,
basing the strength requirement of the lower anchorages on forces
generated by the 6-year-old dummy best ensures that the anchorages will
be able to withstand the loads generated by a child in a crash.
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\29\ NHTSA has granted a December 4, 1997 petition for
rulemaking from Kathleen Weber asking NHTSA to amend Standard 213 to
permit manufacturers to design booster seats with a top tether and
to attach the tether during compliance testing with a 48 lb dummy.
If adopted, the requested amendment would likely result in
manufacturers designing booster seats for children weighing up to
and possibly more than 45 lb.
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[[Page 10806]]
The agency realizes that the 11,000 N static load requirement
results in a more severe load than the 11,000 N load generated in
Transport Canada's dynamic test. It is considered to be more severe
because this final rule adopts the specifications of the NPRM
concerning the periods for attaining and holding the required loads.
The NPRM proposed that the force be applied to each anchorage within 30
seconds, with an onset rate not exceeding 135,000 N per second, and
maintained for 10 seconds. While the 11,000 N static load may be more
demanding than a 11,000 N dynamic load in this instance, it ensures
that the child restraint anchorage system will perform adequately under
most crash conditions, with (as explained above) a wide range of
children. NHTSA is not aware of test data that justifies reducing the
margin of safety afforded by the 11,000 N static load requirement.
The agency also realizes that the 11,000 N static load requirement
of this final rule differs from the draft ISO standard, which specifies
a static load requirement of 8,000 N. NHTSA is unaware of the basis for
the 8,000 N requirement. There are no test data that NHTSA is aware of
that justify setting the requirement at 8,000 N.
With regard to the proposed force application and hold periods,
Ford commented that the periods are unrealistically long, and not
harmonized with European anchor test regulations and practices. Ford
believed that the European periods for attaining and holding the test
force would be more representative of real world crash situations.
Further, the commenter stated, the proposed force application period of
30 seconds reflects forty-year-old test equipment technology, whereas
current state-of-the-art test equipment can apply the test loads in
less than 1 second. Ford stated that it supports the load attainment
and hold specifications of the ISO draft standard, which specify a test
force application period of 2 seconds and hold period of 0.25 seconds.
The force attainment and hold requirements of today's final rule
for the lower anchorages are based on Standard 210 and the NPRM.
Standard 210 sets strength requirements for vehicle seat belt
anchorages. Because today's child restraint systems are secured to the
vehicle seat by way of the vehicle's seat belts, which are anchored to
the vehicle by the seat belt anchorages, Standard 210's strength
requirements establish the level of performance that the current
anchorage system for child restraint systems must meet.
The issue of whether Standard 210's force attainment and hold
requiremen
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