Maryland Attorney General Opinion 107oag153

Gen. 153] 153

CONSTITUTIONAL LAW

SEARCH AND SEIZURE – CANNABIS – WHETHER THE PARTIAL

LEGALIZATION OF CANNABIS UNDER MARYLAND LAW

WILL AFFECT THE AUTHORITY OF MARYLAND POLICE

OFFICERS TO CONDUCT SEARCHES BASED ON THE ODOR

OF CANNABIS

December 1, 2022

The Honorable Bill Ferguson

President of the Senate of Maryland

The Honorable Adrienne A. Jones

Speaker of the House of Delegates of Maryland

At the November 2022 general election, Maryland voters

ratified an amendment to the Maryland Constitution to allow

individuals who are 21 or older to legally possess and use cannabis

beginning on July 1, 2023, subject to further regulation and

restriction by the General Assembly.1 Because of restrictions

already enacted by the General Assembly that were contingent on

passage of the constitutional amendment, the practical result of that

amendment will be the partial legalization, not the full legalization,

of cannabis for those over 21 years of age. More specifically, that

legislation will, starting July 1, allow an adult over 21 to possess

up to 1.5 ounces of cannabis without penalty. Possession of more

than 1.5 ounces but less than 2.5 ounces will be a civil offense, and

possession of 2.5 ounces or more will remain a crime. The General

Assembly has requested our opinion on “the impact of cannabis

legalization on the authority of police officers to conduct searches

of individuals and vehicles based on detection of the odor of burnt

or unburnt cannabis, including in cases involving suspicion of

possession with intent to distribute cannabis, growing or

manufacturing cannabis or cannabis products, or driving under the

influence of cannabis.” 2022 Md. Laws, ch. 26, § 12.

Absent action by the General Assembly to impose limits on

police searches beyond what the United States Constitution or the

Maryland Constitution would require, these are questions that the

courts will ultimately have to resolve. All we can do is predict, as

best we can, how the courts will resolve the questions, using the

1

Effective June 1, 2022, the term “cannabis” replaced all references

to “marijuana” in the Maryland Annotated Code. 2022 Md. Laws, ch.

26, §§ 13, 19. Thus, we use the term “cannabis,” rather than

“marijuana,” throughout this opinion.

154 [107 Op. Att’y

limited body of existing precedent from the Court of Appeals of

Maryland2 as our most important guide. Under Maryland’s current

statutory scheme, which has decriminalized but not legalized some

possession and use of recreational cannabis and will remain largely

in effect until July 1, 2023, the Court has said that the odor of

cannabis, standing alone, authorizes a police officer to search a

vehicle but does not allow an officer to arrest and search a person.

In transitioning to the impending partial legalization regime, the

most difficult question is whether, once some use and possession

of cannabis becomes legal on July 1, the odor of cannabis

emanating from a vehicle, standing alone, will still authorize a

police officer to search a vehicle, though there are other questions

that we examine as well.

Based on existing precedent, it is our opinion that, although

not entirely clear, the Court of Appeals is more likely to hold that

the odor of cannabis emanating from a vehicle will still justify a

police officer’s search of that vehicle after July 1, 2023. We realize

it might seem counterintuitive, at first glance, that the odor of a

drug that will often be legal to possess under Maryland law would

justify such a search. But a closer look at the Court’s precedents

suggests that the Court is more likely to reach that conclusion. That

is because, to conduct a search of a vehicle under the Constitution,

an officer needs only probable cause to believe that the vehicle

contains evidence of a crime, not that a person in the vehicle has

committed or is committing a crime. And, even after Maryland

eliminated criminal penalties for the possession and use of some

amount of recreational cannabis in 2014, the Court of Appeals has

still found that the odor of cannabis coming from a vehicle provides

probable cause to believe that the vehicle may contain evidence of

crimes such as possession of a criminal amount of cannabis, driving

under the influence of cannabis, possession of cannabis with the

intent to distribute, and the illegal distribution of cannabis.

Because all those crimes will remain on the books under the new

partial legalization regime (and because probable cause requires

only a fair probability, not a more-than-fifty-percent likelihood,

that evidence of a crime is present in the vehicle), we cannot say

that the Court would depart from its prior reasoning after July 1.

2

At the November 2022 election, Maryland voters also ratified an

amendment that will change the name of the Court of Appeals of

Maryland to the Supreme Court of Maryland and will change the name

of the Court of Special Appeals to the Appellate Court of Maryland. But

because the final steps in the process for amending the Constitution have

not yet been completed, see Md. Const., Art. XIV, § 1 (requiring a

proclamation by the Governor), we will continue to refer to these courts

by their soon-to-be obsolete names.

Gen. 153] 155

That is especially true given that the General Assembly has not yet

set up a legal marketplace for the sale of recreational cannabis in

Maryland, which means that cannabis found in a vehicle will

presumably often be evidence of the illegal sale of cannabis, even

if the dealer is not in the vehicle.

To be clear, however, the odor of cannabis coming from a

vehicle will not, standing alone, authorize a police officer’s search

of the vehicle’s occupants. We also note that the partial

legalization of cannabis calls into question the authority of police

officers to use canines that are trained to detect the odor of cannabis

to establish probable cause to search a vehicle. Under current law,

canine sniffs are ordinarily not considered “searches” under the

Constitution because they can reveal only the presence or absence

of contraband and, thus, do not invade any reasonable expectation

of privacy. But, once the law changes so that only certain amounts

of cannabis will be contraband, the use of a police canine to sniff

for cannabis may itself constitute a search, which would require

probable cause from some other source, rather than serve as the

basis for probable cause.

Outside of the vehicle context, the odor of cannabis

emanating from an individual, without more, will not justify a

police officer’s arrest and search of that person. After all, even

before the State’s partial legalization scheme has taken effect, the

Court of Appeals has already said that the odor of cannabis, by

itself, does not give an officer probable cause to make an arrest and

conduct a search incident to that arrest. But the odor of cannabis

will likely still permit a police officer to briefly detain the person

to investigate whether they have a criminal amount of cannabis.

And the odor of cannabis will still be a factor that may contribute,

under the totality of the circumstances, to an officer’s authority to

arrest and search a person.

I

Background

For decades, the possession or use of any amount of cannabis

in Maryland was a crime punishable by incarceration and a fine.

See, e.g., Md. Code Ann., Crim. Law (“CL”) § 5-601 (2012 Repl.

Vol.) (criminalizing the possession of a “controlled dangerous

substance”); id. § 5-101(f) (defining “controlled dangerous

substance” to include a drug listed in Schedule I of the Maryland

controlled dangerous substances statute), § 5-402(d)(1)(vii)

(including cannabis within Schedule I); see also id. § 5-402(a)(3)

(providing that Schedule I under Maryland law consists of each

156 [107 Op. Att’y

controlled dangerous substance that the federal government has

designated a Schedule I controlled dangerous substance); 21 U.S.C.

§ 812, Schedule I (c)(10) (listing “[m]arihuana”—what Maryland

law now refers to as cannabis—as a Schedule I drug under the

federal statute).3

In 2014, the General Assembly decriminalized—but did not

legalize—the use or possession of less than 10 grams (about 0.35

ounces) of cannabis. 2014 Md. Laws, ch. 158 (codified at CL

§ 5-601(c)(2)); Robinson v. State, 451 Md. 94, 96-97 (2017).

Under this law, which is still in effect, the use or possession of less

than 10 grams of cannabis is no longer a crime punishable by

incarceration but a civil offense for which an individual may be

fined. CL § 5-601(c)(2).4 The use or possession of 10 grams or

more of cannabis remains a crime, punishable by both incarceration

and a fine. Id.

Since 2014, the General Assembly has also expanded

Maryland’s medical cannabis program and clarified that cannabis

does not include hemp. As to medical cannabis, the General

Assembly in 2014 authorized licensed dispensaries to provide

medical cannabis to card-carrying patients. 2014 Md. Laws, ch.

256. To accommodate the use of cannabis for medical purposes,

Maryland’s criminal laws now recognize several affirmative

defenses for the use or possession of cannabis for “medical

necessity” or for “palliative relief from [a] debilitating medical

condition.” See CL § 5-601(c)(3)(ii) (providing that, in a

prosecution for criminal use or possession of cannabis, a court must

dismiss the charge upon finding that the person used or possessed

cannabis because of “medical necessity”), § 5-601(c)(3)(iii)(1)

(providing for an affirmative defense when the use or possession

of cannabis is for “therapeutic or palliative relief from [a]

debilitating medical condition”). Section 13-3313(a) of the Health-

3

Under federal law, a substance is classified as a Schedule I drug if:

“(A) [t]he drug or other substance has a high potential for abuse”;

“(B) [t]he drug or other substance has no currently accepted medical use

in treatment in the United States”; and “(C) [t]here is a lack of accepted

safety for use of the drug or other substance under medical supervision.”

21 U.S.C. § 812(b)(1).

4

If the person using or possessing less than 10 grams of cannabis is

under 21, a court must also order the person to attend a drug education

program, refer the person to an assessment for substance abuse disorder,

and, if necessary, refer the person to substance abuse treatment. CL

§ 5-601(c)(2)(ii)(4)(A). These additional consequences apply also to the

third or subsequent offense committed by a person who is 21 or older.

CL § 5-601(c)(2)(ii)(4)(B).

Gen. 153] 157

General Article also provides that a patient or caregiver of a patient

using medical cannabis may not be subject to arrest, prosecution,

or any civil or administrative penalty so long as the person acts in

accordance with the State’s medical cannabis laws.

As for hemp, the General Assembly in 2015 legalized

industrial hemp, which it defined to mean “the plant Cannabis

sativa L. and any part of such plant, whether growing or not, with

a [THC] concentration that does not exceed 0.3% on a dry weight

basis.” 2015 Md. Laws, ch. 456.5 The law also excluded industrial

hemp from the definition of cannabis (then called “marijuana”). Id.

In 2019, the General Assembly renamed “industrial hemp” to

“hemp” and expanded the definition to include “all derivatives,

extracts, cannabinoids, isomers, acids, salts, and salts of isomers”

of the Cannabis sativa L. plant with a THC concentration that does

not exceed 0.3% on a dry weight basis. 2019 Md. Laws, ch. 228.

Cannabis is still defined to exclude hemp. CL § 5-101(r)(2)(vi).

Federal law also excludes hemp from Schedule I controlled

substances. 21 U.S.C. § 812, Schedule I (c)(17).

During the 2022 legislative session, the General Assembly

passed two major bills concerning the legalization of recreational

cannabis. The first, House Bill 1, proposed an amendment to the

Maryland Constitution to legalize possession and use of cannabis

under certain conditions. 2022 Md. Laws, ch. 45. The amendment,

approved by voters in Maryland’s November 2022 general

election, provides that an individual who is at least 21 years old

will be able to possess and use cannabis beginning on July 1, 2023,

subject to regulation by the General Assembly.6 Id.

The second bill, House Bill 837, addresses the limits of the

impending legalization of cannabis and was largely contingent

upon voters’ approval of the constitutional amendment. 2022 Md.

5

THC, the more common name for delta-9-tetrahydrocannabinol, is a

mind-altering chemical found in the cannabis plant. National Inst. on

Drug Abuse, Cannabis (Marijuana), https://nida.nih.gov/research-

topics/cannabis-marijuana (last visited Nov. 30, 2022).

6

Under legislation contingent on voters’ approval of the

constitutional amendment, the use or possession of up to 1.5 ounces of

cannabis will become a civil offense from January 1, 2023, through June

30, 2023, the day before the use or possession of that amount will

become legal for individuals who are at least 21 years old. 2022 Md.

Laws, ch. 26, § 3 (amending CL § 5-601), § 15. Effective July 1, 2023,

the use or possession of up to 1.5 ounces of cannabis will be a civil

offense only for those who are younger than 21 years old. 2022 Md.

Laws, ch. 26, § 4 (amending CL § 5-601), § 16.

158 [107 Op. Att’y

Laws, ch. 26. The legislation specifies that a person who is at least

21 or older will not be subject to any criminal or civil penalties for

possessing up to 1.5 ounces (about 42.5 grams) of cannabis (the

“personal use amount”).7 2022 Md. Laws, ch. 26, § 4 (amending

CL §§ 5-101, 5-601). The use or possession of the “civil use

amount”—more than 1.5 ounces of cannabis but not more than 2.5

ounces (about 71 grams)8—will be a civil offense, punishable by a

fine but not incarceration. Id. § 4 (amending CL §§ 5-101, 5-601).

The use or possession of more than 2.5 ounces will be a crime. Id.

Several other existing cannabis-related offenses will remain

subject to criminal or civil penalties under the legislation. For

example, it will remain a crime to drive under the influence of

cannabis,9 to cultivate more than two cannabis plants,10 and to

7

The “personal use amount” is alternatively defined as an amount of

concentrated cannabis that does not exceed 12 grams, an amount of

cannabis products containing THC that does not exceed 750 milligrams,

or two or fewer cannabis plants. 2022 Md. Laws, ch. 26, § 4 (amending

CL § 5-101). Concentrated cannabis products are made by extracting

substances from the plant into a form with a much higher THC

concentration than the flower. L. Cinnamon Bidwell et al., Exploring

Cannabis Concentrates on the Legal Market: User Profiles, Product

Strength, and Health-Related Outcomes, 8 Addictive Behavs. Reps. 102,

102 (2018).

8

The civil use amount is defined alternatively as an amount of

concentrated cannabis that exceeds 12 grams but does not exceed 20

grams, or an amount of cannabis products containing THC that exceeds

750 milligrams but does not exceed 1,250 milligrams. 2022 Md. Laws,

ch. 26, § 4 (amending CL § 5-101).

9

Md. Code Ann., Transp. § 21-902(c) (providing that a person “may

not drive or attempt to drive any vehicle while so far impaired by any

drug, any combination of drugs, or a combination of one or more drugs

and alcohol that the person cannot drive a vehicle safely”), § 21-902(d)

(providing that a person “may not drive or attempt to drive any vehicle

while the person is impaired by any controlled dangerous substance . . .

if the person is not entitled to use the controlled dangerous substance

under the laws of this State”); see also 2022 Md. Laws, ch. 26, § 4

(amending CL § 5-601(d) to specify that legalization of the personal use

amount of cannabis and decriminalization of the civil use amount “may

not be construed to affect the laws relating to . . . operating a vehicle or

vessel while under the influence of or while impaired by a controlled

dangerous substance”).

10

2022 Md. Laws, ch. 26, § 4 (adding new CL § 5-601.2). Only

individuals 21 and older will be allowed to grow cannabis, and plants

may not be cultivated in a location where the plants are subject to public

Gen. 153] 159

distribute cannabis or possess cannabis with the intent to distribute

it.11 The General Assembly has not yet enacted legislation

establishing a legal marketplace for recreational cannabis, so—at

least at first—the sale of cannabis will remain illegal even when

the use and possession of cannabis is not. It will be a civil offense

to smoke cannabis in public,12 to smoke it on mass transit and in

other indoor spaces regulated under the Clean Indoor Air Act,13 and

view. Id. Violation of this law will be a misdemeanor subject to a three-

year prison sentence and/or a fine of up to $5,000. Id. Licensed medical

cannabis growers will not be limited to growing only two plants. See

Maryland Medical Cannabis Commission, Growers FAQ,

https://mmcc.maryland.gov/Pages/growers.aspx (last visited Nov. 30,

2022) (noting that regulations do not specify the maximum number of plants

that a licensed grower may cultivate); see also Md. Code Ann., Health-Gen.

§ 13-3306(h) (providing that a licensed grower may not be penalized for

cultivating plants for a medical cannabis processor or dispensary).

11

The law currently prohibits the possession of “a controlled

dangerous substance in sufficient quantity reasonably to indicate under

all circumstances an intent to distribute or dispense [the] controlled

dangerous substance.” CL § 5-602(a)(2). Licensed medical cannabis

dispensaries may not be penalized for distributing “medical cannabis,

products containing medical cannabis, related supplies, or educational

materials for use by a qualifying patient, a caregiver, or an academic

research representative.” Md. Code Ann., Health-Gen. § 13-3307(g).

The law criminalizing possession with intent to distribute will change on

January 1, 2023, to specify that possession of the civil use amount or the

personal use amount of cannabis, “without other evidence of an intent to

distribute or dispense,” does not constitute possession with the intent to

distribute cannabis. 2022 Md. Laws, ch. 26, § 5 (adding CL § 5-602(b)),

§ 18 (specifying that this change will take effect January 1, 2023). This

will apparently codify a principle that Maryland courts have long

recognized, i.e., that “no specific quantity of drugs has been delineated

that distinguishes between a quantity from which one can infer [an intent

for personal use as opposed to an intent to distribute] and a quantity from

which one cannot make such an inference.” Collins v. State, 89 Md.

App. 273, 279 (1991). Beginning July 1, 2023, individuals who are at

least 21 years old will be allowed to share with others who are at least

21 years old the personal use amount of cannabis, without any civil or

criminal penalties. 2022 Md. Laws, ch. 26, § 4 (adding CL § 5-602(c)),

§ 16 (specifying that this change will take effect July 1, 2023).

12

2022 Md. Laws, ch. 26, § 4 (providing that, under CL § 5-601(c)(4),

smoking cannabis in public will be a civil offense punishable by a fine

of up to $250 for a first finding of guilt, and a fine of up to $500 for a

second or subsequent finding of guilt).

13

2022 Md. Laws, ch. 26, § 5 (amending Md. Code Ann., Health-

Gen. §§ 24-501 through 24-504 to clarify that a person may not smoke

160 [107 Op. Att’y

to smoke cannabis in a passenger area of a motor vehicle on a

highway.14

Regardless of the impending legalization of some possession

and use of cannabis under Maryland law, the drug will remain a

controlled substance that is illegal to possess or distribute under

federal law. See 21 U.S.C. § 812 (listing marijuana as a Schedule

I controlled substance), § 841 (imposing criminal penalties for the

manufacture, distribution, and possession with intent to distribute

a controlled substance), § 844(a) (imposing criminal penalties for

simple possession of a controlled substance).15

II

Analysis

The question before us is what impact the impending

legalization of certain amounts of cannabis under Maryland law

will have on the authority of police officers to conduct searches of

vehicles and individuals based on the odor of cannabis. Police

searches are subject to the Fourth Amendment to the U.S.

Constitution, which protects against unreasonable searches and

seizures.16 We thus begin our analysis by examining the Fourth

cannabis in an indoor space where tobacco smoking is already unlawful:

an indoor area open to the public, an indoor place in which meetings are

open to the public under the Open Meetings Act, mass transit, or an

indoor place of employment).

14

2022 Md. Laws, ch. 26, § 6 (amending CL § 10-125 to prohibit an

occupant of a motor vehicle from smoking cannabis in a passenger area

of a motor vehicle on a highway and amending Md. Code Ann., Transp.

(“TR”) § 21-903 to prohibit a driver from smoking or consuming

cannabis in a passenger area of a motor vehicle on a highway). Violation

of CL § 10-125 will be a civil offense, subject to a fine not to exceed $25.

CL § 10-126(g). Violating TR § 21-903 may result in the issuance of a

traffic citation. TR § 26-201.

15

On October 6, 2022, President Joe Biden pardoned all people

convicted of cannabis possession under federal law and said that his

administration would review whether cannabis should remain a Schedule

I drug. White House, Statement from President Biden on Marijuana

Reform (Oct. 6, 2022), https://www.whitehouse.gov/briefing-

room/statements-releases/2022/10/06/statement-from-president-biden-

on-marijuana-reform/.

16

Maryland’s constitution has an analogous provision, Article 26 of

the Declaration of Rights. But because Article 26 has historically been

read in pari materia with the Fourth Amendment, see, e.g., King v. State,

Gen. 153] 161

Amendment principles that govern police searches generally. We

then consider how Maryland’s appellate courts have applied these

principles in cases involving the odor of cannabis—first, under the

State statutory scheme that, until 2014, criminalized the possession

of any amount of cannabis, and second, under the current State

statutory scheme, which has decriminalized the possession and use

of less than 10 grams of cannabis and will remain in effect, with

few changes,17 until July 1, 2023.

A. Constitutional Principles that Apply to Police Searches

Generally

The Fourth Amendment, which protects against

“unreasonable governmental intrusions,” Winston v. Lee, 470 U.S.

753, 767 (1985), generally requires a police officer to obtain a

warrant before conducting a search, e.g., Riley v. California, 573

U.S. 373, 382 (2014). A judge shall issue a warrant only if the

officer has demonstrated probable cause for the search, i.e., “a fair

probability that contraband or evidence of a crime will be found in

a particular place.” Illinois v. Gates, 462 U.S. 213, 238 (1983).

“Nevertheless, because the ultimate touchstone of the Fourth

Amendment is ‘reasonableness,’ the warrant requirement is subject

to certain exceptions.” Brigham City v. Stuart, 547 U.S. 398, 403

(2006). Two of those exceptions are relevant to our analysis: the

434 Md. 472, 482 (2013), we focus our analysis on the federal

constitutional provision. The United States Supreme Court is, of course,

“the final arbiter of the meaning and application of the [federal]

Constitution,” R & T Constr. Co. v. Judge, 323 Md. 514, 520 (1991),

including the Fourth Amendment. But the Supreme Court has yet to

consider a Fourth Amendment challenge to a search based on the odor

of cannabis in a state that has decriminalized or legalized some use and

possession of cannabis. Moreover, Maryland’s courts would be the first

to address a Fourth Amendment challenge in a State prosecution under

the impending legalization scheme. We thus focus our attention on how

Maryland’s appellate courts have applied the Fourth Amendment in

cases involving the odor of cannabis.

17

As noted above, no possession or use of recreational cannabis will

be legal until July 1, 2023, but the amount that a person may possess

subject only to civil penalties (as opposed to criminal penalties) will

increase from 10 grams to 1.5 ounces beginning January 1, 2023, and

continuing through June 30, 2023. 2022 Md. Laws, ch. 26, § 3

(amending CL § 5-601). The law criminalizing possession with intent to

distribute will also change on January 1, 2023, to specify that possession

of the civil use amount or the personal use amount of cannabis, “without

other evidence of an intent to distribute or dispense,” does not constitute

possession with the intent to distribute cannabis. Id. §§ 5, 18.

162 [107 Op. Att’y

search incident to arrest exception, and the automobile exception

(also known as the Carroll doctrine).

1. Search Incident to Arrest Exception

Under the search incident to arrest exception, police may

lawfully search a person pursuant to a warrantless arrest if the

police have probable cause to believe that the person “has

committed a felony or is committing a felony or misdemeanor in

the presence of the police.” Pacheco v. State, 465 Md. 311, 321-

22 (2019) (citing Maryland v. Pringle, 540 U.S. 366, 369-70

(2003)). Probable cause is “a fluid concept,” Gates, 462 U.S. at

232, “incapable of precise definition or quantification into

percentages because it deals with probabilities and depends on the

totality of the circumstances,” Pringle, 540 U.S. at 371. The

standard takes into account “the factual and practical

considerations of everyday life,” id. at 370 (quoting Gates, 462

U.S. at 231), requiring less evidence “than would justify conviction

but more evidence than that which would arouse a mere suspicion,”

Doering v. State, 313 Md. 384, 403 (1988). Thus, to justify an

arrest, a police officer must be able to point to “specific and

articulable facts,” which, taken together, “would lead a reasonably

cautious person to believe” that a crime had been or was being

committed by the person arrested. State v. Wallace, 372 Md. 137,

148 (2002). But probable cause is “not a high bar,” State v.

Johnson, 458 Md. 519, 535 (2018) (quoting District of Columbia

v. Wesby, 138 S. Ct. 577, 586 (2018)), requiring less than proof by

the preponderance of the evidence, Freeman v. State, 249 Md. App.

269, 301-02 (2021).

The justifications for the search incident to arrest exception

are to preserve evidence and to protect police officers by ensuring

that the arrested person does not have weapons. See, e.g., Arizona

v. Gant, 556 U.S. 332, 338 (2009). Under this exception, police

may search the arrestee’s person and the area within the arrested

person’s immediate control. Id. at 339.

2. Automobile Exception

Another exception to the warrant requirement is the

automobile exception, also known as the Carroll doctrine. The

U.S. Supreme Court first articulated this exception in Carroll v.

United States, 267 U.S. 132 (1925), a Prohibition-era case in which

police had probable cause to believe that a car they observed

driving on a road contained illegal liquor. Officers stopped and

searched the vehicle, discovered and seized illegal liquor, and

Gen. 153] 163

arrested the occupants. Id. In upholding the warrantless search and

seizure, the Carroll Court reasoned that “a ‘necessary difference’

exists between searching ‘a store, dwelling house or other

structure’ and searching ‘a ship, motor boat, wagon or automobile’

because a ‘vehicle can be quickly moved out of the locality or

jurisdiction in which the warrant must be sought.’” Collins v.

Virginia, 138 S. Ct. 1663, 1669 (2018) (quoting Carroll, 267 U.S.

at 153). Thus, under the Carroll doctrine, police may conduct a

warrantless search of “an automobile and the containers within it

where they have probable cause to believe contraband or evidence

[of a crime] is contained.” California v. Acevedo, 500 U.S. 565,

580 (1991).18 The justifications for this exception are the “ready

mobility” and “pervasive and continuing governmental regulation”

of vehicles, Collins, 138 S. Ct. at 1669-70, which has reduced

individuals’ expectation of privacy in automobiles, Pennsylvania

v. Labron, 518 U.S. 938, 940 (1996).

The automobile exception “requires the same ‘quantum of

evidence’”—probable cause—as the search incident to arrest

exception, but each exception “requires a showing of probabilities

as to somewhat different facts and circumstances.” Pacheco, 465

Md. at 324-25 (quoting 2 Wayne R. LaFave, Search and Seizure:

A Treatise on the Fourth Amendment § 3.1(b), at 7 (5th ed. 2012)).

Whereas the search incident to arrest exception requires probable

cause to believe that the arrested person has committed a crime, see

supra Part II.A.1, the Carroll doctrine only requires probable cause

to believe that the vehicle contains contraband or evidence of a

crime, Florida v. Harris, 568 U.S. 237, 243 (2013). When police

have the requisite probable cause, they may search “every part of

the vehicle and its contents that may conceal the object of the

search.” Wyoming v. Houghton, 526 U.S. 295, 301 (1999)

(emphasis omitted) (quoting United States v. Ross, 456 U.S. 798,

825 (1982)). But “the scope of the automobile exception extends

no further than the automobile itself,” Collins, 138 S. Ct. at 1671,

and probable cause to search a vehicle does not automatically

provide probable cause to search an occupant of the vehicle, State

v. Wallace, 372 Md. 137, 144 (2002).

18

“Although typically described as the automobile exception to the

Fourth Amendment warrant requirement, the Carroll exception also

applies to searches of other vehicles.” Lewis v. State, 470 Md. 1, 20 n.6

(2020); see also Carroll, 267 U.S. at 153 (characterizing “ship[s], motor

boat[s], wagon[s], [and] automobile[s]” as “vehicle[s] [that] can be

quickly moved”); California v. Carney, 471 U.S. 386, 393 n.2 (1985)

(“With few exceptions, the courts have not hesitated to apply the vehicle

exception to vehicles other than automobiles.”).

164 [107 Op. Att’y

3. Techniques That a Police Officer May Use to Develop

Probable Cause

When an officer lacks probable cause to believe that a person

has committed a crime or that a vehicle contains contraband or

evidence of a crime, the officer may investigate further, employing

techniques that fall short of an arrest or a search under the Fourth

Amendment.

i. Terry Stops

If an officer reasonably suspects that a person is involved in

criminal activity but lacks probable cause to make an arrest, the

officer may nonetheless briefly detain the person, whether the

person is on foot or in a vehicle, to investigate. See, e.g., Kansas

v. Glover, 140 S. Ct. 1183, 1187 (2020); Navarette v. California,

572 U.S. 393, 396-97 (2014). This brief investigatory detention,

commonly known as a Terry stop,19 is “considered less intrusive

than a formal custodial arrest,” Wilson v. State, 409 Md. 415, 440

(2009), and, thus, “requires a less demanding level of suspicion

than probable cause,” Trott v. State, 473 Md. 245, 255 (2021). That

less demanding standard is known as “reasonable suspicion.”

As with probable cause, reasonable suspicion “takes into

account ‘the totality of the circumstances—the whole picture.’”

Navarette, 572 U.S. at 397 (quoting United States v. Cortez, 449

U.S. 411, 417 (1981)). But while “a mere hunch does not create

reasonable suspicion,” the standard requires “considerably less

than proof of wrongdoing by a preponderance of the evidence and

obviously less than is necessary for probable cause.” Id. The

“reasonable suspicion” standard is less demanding in another way

too. As the Supreme Court has explained:

Reasonable suspicion is a less demanding

standard than probable cause not only in the

sense that reasonable suspicion can be

established with information that is different

in quantity or content than that required to

establish probable cause, but also in the sense

that reasonable suspicion can arise from

information that is less reliable than that

required to show probable cause.

19

It was in Terry v. Ohio, 392 U.S. 1, 20-22 (1968), that the Supreme

Court first recognized that an officer may briefly detain someone that the

officer reasonably suspects of committing a crime.

Gen. 153] 165

Alabama v. White, 496 U.S. 325, 330 (1990). When an officer has

reasonable suspicion, the officer may detain the person “only . . .

as long as it takes [the] police officer to confirm or dispel [their]

suspicions.” Swift v. State, 393 Md. 139, 150 (2006); see also

Hiibel v. Sixth Jud. Dist. Ct. of Nevada, 542 U.S. 177, 185 (2004)

(noting that reasonable suspicion “permits the officer to stop the

person for a brief time and take additional steps to investigate

further”).

ii. Dog Sniffs

One way that police commonly confirm or dispel suspicions

of criminal activity (especially during traffic stops) is by using a

dog specially trained to detect the presence of contraband,

including illegal drugs. See, e.g., Wilkes v. State, 364 Md. 554, 565

(2001) (involving a police dog trained to alert to cocaine, heroin,

cannabis, and hashish); Emory v. State, 101 Md. App. 585, 635

(1994) (involving a certified cannabis-sniffing dog). “A dog’s

sense of smell is somewhere between 100,000 and one million

times stronger than a human’s sense of smell.” Melanie

Reid, Goodbye Marijuana Schedule I—Welcome to a Post-

Legalization World, 18 Ohio St. J. Crim. L. 169, 183 (2020). One

might expect, therefore, that use of a police canine to detect drugs

could rise to the level of a search under the Fourth Amendment,

given that it is a special technique that effectively enhances an

officer’s senses beyond ordinary human capacity. Cf. Kyllo v.

United States, 533 U.S. 27, 29-30, 34-35, 40 (2001) (holding that

police officers conducted a search when, from their vehicle parked

on a public street, they used a thermal-imaging device to detect

infrared radiation emanating from a house).

But, in cases decided before the widespread legalization of

cannabis in many states, the Supreme Court has said that a dog sniff

is generally not “a ‘search’ within the meaning of the Fourth

Amendment.” United States v. Place, 462 U.S. 696, 707 (1983).

The Court’s rationale for that conclusion has been that a “search”

generally occurs only when a government inspection “intrude[s]

upon a legitimate expectation of privacy,” Illinois v. Andreas, 463

U.S. 765, 771 (1983), and a trained dog’s “sniff discloses only the

presence or absence of . . . contraband,” Place, 462 U.S. at 707, in

which an individual has no legitimate privacy interest, Illinois v.

Caballes, 543 U.S. 405, 408 (2005). Indeed, “dog sniffs are unique

in their narrow yes/no determination of the presence of

narcotic[s].” Fitzgerald v. State, 384 Md. 484, 501 (2004); accord

166 [107 Op. Att’y

Place, 462 U.S. at 707 (recognizing that “the canine sniff is sui

generis”).20

In the pre-legalization context, therefore, the Supreme Court

has held that a dog sniff of a vehicle during a traffic stop is

ordinarily not a search subject to the Fourth Amendment, Caballes,

543 U.S. at 409-10, even though police officers’ use of other sense-

enhancing techniques may sometimes constitute a search, see, e.g.,

Kyllo, 533 U.S. at 29-30. In distinguishing between dog sniffs and

the use of some other techniques that have been found to be

searches under the Fourth Amendment, a key consideration is

whether the technique at issue might reveal the presence of

noncontraband items. See, e.g., Caballes, 543 U.S. at 409-10

(pointing out that “[c]ritical to th[e] [Kyllo] decision was the fact

that the device was capable of detecting lawful activity—in that

case, intimate details in a home”—whereas “[a] dog sniff

conducted during a concededly lawful traffic stop . . . reveals no

information other than the location of a substance that no individual

has any right to possess”); Fitzgerald v. State, 153 Md. App. 601,

684-85 (2003) (contrasting the “limited and binary nature” of a dog

sniff, which reveals only “the presence or absence of contraband

drugs,” with the use of heat-sensing technology in Kyllo, which

“detected . . . unusual amounts of heat . . . generated inside the

home, a phenomenon that is not itself criminal and could well have

had a non-criminal explanation”), aff’d, 384 Md. 484 (2004).

Because trained police dogs have historically been able to detect

only the presence or absence of contraband, the Supreme Court has

said that dog sniffs are generally not searches under the Fourth

Amendment.21

20

An officer’s detection of the odor of cannabis using the officer’s

nose, unaided by the use of a specially trained dog, is clearly not a

“search” under the Fourth Amendment, so long as the officer is “lawfully

present” at the place where the officer smells the odor. 1 Wayne R.

LaFave, Search and Seizure: A Treatise on the Fourth Amendment

§ 2.2(a) (6th ed. 2020). Under “what might be called the ‘plain smell’

rule,” “no search in a Fourth Amendment sense has occurred,” because

no one has a reasonable expectation of privacy in “odors emanating from

private premises, from a vehicle, or from some personal effects nearby”

and detectable by “lawfully positioned agents ‘with inquisitive nostrils.’”

Id. (quoting United States v. Johnston, 497 F.2d 397, 398 (9th Cir. 1974)).

21

An exception is when police use a canine to sniff the front door of

a home, an act that violates “the traditional property-based understanding

of the Fourth Amendment,” which prohibits warrantless intrusions into

a home or the area immediately adjacent without the permission of the

homeowner. Florida v. Jardines, 569 U.S. 1, 6, 11 (2013). A dog sniff

Gen. 153] 167

iii. Frisks

In addition to briefly detaining someone if the officer has

reasonable suspicion that the person is engaged in criminal activity,

an officer may conduct a frisk of the person for weapons if the

officer has reasonable suspicion that the person stopped is armed

and dangerous. E.g., Arizona v. Johnson, 555 U.S. 323, 326-27

(2009). The officer must be able to articulate specific facts,

particularized to the person stopped, that reasonably indicate that

the person has a weapon and is presently dangerous. E.g., Ybarra

v. Illinois, 444 U.S. 85, 93-94 (1979). The purpose of the frisk is

“not to discover evidence of crime, but to allow the officer to

pursue [their] investigation without fear of violence.” Adams v.

Williams, 407 U.S. 143, 146 (1972). Thus, an officer need not

establish probable cause before frisking someone the officer

reasonably suspects is armed and dangerous. Because the purpose

of a Terry frisk is to detect the presence of a dangerous weapon, the

scope is limited to patting down a detainee’s outer clothing.

Lockard v. State, 247 Md. App. 90, 105 (2020). This “pat-down”

is sufficient to discover whether the person has a gun, knife, or

other dangerous instrument. Id.

4. Summary

To summarize the constitutional principles that ordinarily

apply in cases involving government searches and seizures, a

police officer generally must obtain a warrant before conducting a

search. But an officer need not obtain a warrant before searching

a person if the officer has a lawful reason to arrest that person.

Likewise, an officer need not obtain a warrant before searching a

vehicle if the officer has probable cause that the vehicle contains

contraband or evidence of a crime. If an officer lacks probable

cause to arrest someone or search a vehicle, the officer may

during a traffic stop on a public roadway does not implicate this property-

based theory and does not violate the Fourth Amendment so long as the

officer has a lawful reason to conduct the traffic stop and the officer does

not prolong the stop simply to allow a canine to arrive and sniff the

vehicle. Once the purpose of “an ordinary traffic stop” “has been

fulfilled, the continued detention of the car and the occupants amounts

to a second detention.” Ferris v. State, 355 Md. 356, 372 (1999). “Thus,

once the underlying basis for the initial traffic stop has concluded, a

police-driver encounter which implicates the Fourth Amendment is

constitutionally permissible only if either (1) the driver consents to the

continuing intrusion or (2) the officer has, at a minimum, a reasonable,

articulable suspicion that criminal activity is afoot” and the canine sniff

would confirm or dispel that suspicion. Id.

168 [107 Op. Att’y

nonetheless briefly detain a person or vehicle, provided the officer

has reasonable suspicion that criminal activity is afoot. During

such a stop, the officer may use a police-trained dog to sniff for

contraband. The officer may also frisk a person if the officer

reasonably suspects that the person is armed and dangerous.

We turn now to how courts have applied these Fourth

Amendment principles in cases involving the odor of cannabis.

B. Police Officers’ Authority, Before the Decriminalization of

Small Amounts of Cannabis, to Conduct Searches Based on

the Odor of Cannabis

Before 2014, when the possession or use of any amount of

cannabis was a crime under Maryland law, the odor of cannabis

provided police a lawful basis to search both individuals and

vehicles. See, e.g., McGurk v. State, 201 Md. App. 23, 52 (2011)

(addressing the search of a person incident to arrest); Wilson v.

State, 174 Md. App. 434, 454-55 (2007) (addressing the search of

a vehicle). This was true whether it was an officer who detected

the odor of cannabis, see, e.g., State v. Harding, 166 Md. App. 230,

236 (2005), or a police dog trained to alert to the presence of illegal

drugs, see, e.g., Gadson v. State, 341 Md. 1, 8 (1995).

As to individuals, the odor of cannabis provided probable

cause to believe that cannabis was present; thus, if an officer could

“localize its source to a person, the officer ha[d] probable cause to

believe that the person ha[d] committed or [was] committing the

crime of possession of [cannabis].” McGurk, 201 Md. App. at 52

(emphasis omitted) (quoting United States v. Humphries, 372 F.3d

653, 659 (4th Cir. 2004)). The probable cause, in turn, authorized

the officer to arrest that person and search them incident to arrest.

See In re D.D., 479 Md. 206, 224 (2022) (recognizing that “the

odor of [cannabis] particularized to a person provided probable

cause for an arrest” before 2014); Pacheco, 465 Md. at 323

(explaining the search incident to arrest exception).

As to vehicles, the odor of cannabis emanating from an

automobile provided police probable cause to believe that cannabis

was present somewhere in that automobile. Wilson, 174 Md. App.

at 454. Thus, the odor authorized an officer to search the entire

vehicle. Id. at 455 & n.7; see also United States v. Ross, 456 U.S.

798, 824-25 (1982) (“If probable cause justifies the search of a

lawfully stopped vehicle, it justifies the search of every part of the

Gen. 153] 169

vehicle and its contents that may conceal the object of the

search.”).22

Probable cause to search a vehicle, however, did not

necessarily establish probable cause to search each of the vehicle’s

occupants. Rather, the Court of Appeals said that, “while [an] alert

[to a car] by a drug dog trained to detect contraband[]

undisputedly[] gave the police probable cause to believe there was

contraband somewhere in the car or on the person of someone in

the car, the canine sniff of the vehicle alone did not amount to

probable cause to then search each of the passengers.” State v.

Wallace, 372 Md. 137, 155-56 (2002). Wallace involved a traffic

stop, during which a police dog alerted to the presence of illegal

drugs in the car. Id. at 141. Police removed the three occupants

from the vehicle and searched them. Id. at 142. The Wallace Court

held that the search of the backseat passenger was illegal because

“there was no probable cause for the officer, at that point in time

on the night in question,” to believe that this particular passenger

had illegal drugs. Id. at 157. The Court elaborated:

Without additional facts that would tend to

establish [the backseat passenger’s]

knowledge and dominion or control over the

contraband before his search, the K-9 sniff of

the car was insufficient to establish probable

cause for a search of a non-owner, non-driver

for possession. Merely sitting in the backseat

of a car did not amount, in this case, to

probable cause specific to [the backseat

22

Wilson involved the odor of burnt cannabis. 174 Md. App. at 438.

According to some out-of-state courts, the odor of burnt cannabis

indicates drug use but not drug trafficking, justifying a search of only a

vehicle’s passenger compartment but not the trunk; in these courts’ view,

only the odor of raw (i.e., unburnt) cannabis indicates drug trafficking,

justifying a search of a vehicle’s trunk. Id. at 446-54 (collecting cases).

The Wilson Court rejected this “burnt-raw” distinction, concluding that

it would not be “unreasonable for an officer to believe that the odor of

burnt [cannabis] indicate[d] current possession of unsmoked [cannabis]

somewhere inside of the vehicle, including the trunk.” Id. at 454-55; see

also id. at 456 (“eliminat[ing] the need to distinguish between burnt,

burning, or raw [cannabis]” when determining whether probable cause

exists to search a vehicle). Consistent with the Wilson Court’s

conclusion, the Court of Appeals has said that “[t]he automobile doctrine

permits the search of ‘every part of the vehicle and its contents that may

conceal the object of the search.’” Pacheco, 465 Md. at 322 (quoting

Wyoming v. Houghton, 526 U.S. 295, 301 (1999)).

170 [107 Op. Att’y

passenger] to search and subsequently arrest

him.

Id. at 156.23 The Court suggested, however, that the outcome might

have been different if the defendant had been the driver or owner

of the vehicle, id. at 156-57, and, four years later, the Court of

Special Appeals stated that a canine’s alert to illegal drugs in a

vehicle with a driver and one other occupant provided “probable

cause to arrest, at the very least, the driver,” who was “a person

with a more significant connection to the car” than a mere

passenger. State v. Ofori, 170 Md. App. 211, 229, 233 (2006).

In sum, when the possession or use of any amount of cannabis

was criminal under Maryland law, police could lawfully conduct a

search incident to arrest of an individual who smelled of cannabis.

If the smell of cannabis came from a vehicle, police could search

the entire vehicle and its contents. But the smell of cannabis

coming from a vehicle did not authorize police to search an

occupant of the vehicle unless additional facts connected that

particular occupant to the cannabis.

C. Police Officers’ Authority, Under the Current Statutory

Scheme, to Conduct Searches Based on the Odor of

Cannabis

Under Maryland’s current statutory scheme—which has

removed the criminal penalties for possession of less than 10 grams

of cannabis but has not legalized it—the odor of cannabis, standing

alone, still provides a police officer justification to search a vehicle,

but it no longer authorizes the search of an individual (though an

officer may briefly detain a person who smells of cannabis to

investigate further). See Robinson v. State, 451 Md. 94, 99 (2017)

(holding that the odor of cannabis emanating from a vehicle

provides a police officer justification to search that vehicle); Lewis

v. State, 470 Md. 1, 10 (2020) (holding that the odor of cannabis

emanating from a person alone does not provide probable cause for

a police officer to arrest and search that person); In re D.D., 479

Md. 206, 215, 217 (2022) (holding that the odor of cannabis on a

23

The Wallace Court suggested that police could have established the

requisite link had “the K-9 . . . sniffed [the passenger], and specifically

alerted to [him], before the officer searched him,” or “[i]f the officers

simply had [the dog] sniff each of the passengers of the car prior to

searching them,” in which case “probable cause might have existed to

search any of the passengers who positively re-alerted the canine to

contraband.” Id. at 156.

Gen. 153] 171

person authorizes a police officer to conduct a brief investigatory

detention).

1. Searches of Vehicles

In Robinson v. State, the Court of Appeals for the first time

considered the impact of decriminalization on a police officer’s

authority to conduct a search based on the odor of cannabis. That

decision involved three different defendants, each of whom had

been arrested following a search of an automobile based on an

officer’s detection of a strong odor of “fresh” (i.e., unburnt)

cannabis coming from the vehicle. Robinson, 451 Md. at 99-106.

Challenging these searches, the defendants argued that the odor of

cannabis no longer provided probable cause to search a vehicle,

because an officer could not tell, from odor alone, whether the car

contained a criminal amount of cannabis or a non-criminal amount

of less than 10 grams. Id. at 106-07.

The Court in Robinson rejected the defendants’ argument,

holding that a police officer still has probable cause to search a

vehicle when the officer detects an odor of cannabis emanating

from the vehicle. Id. at 99. Although the Court acknowledged that

“it is effectively impossible for law enforcement officers to identify

a quantity of [cannabis] based on odor alone,” id. at 130, the Court

noted that possession of less than 10 grams of cannabis, while no

longer criminal, is still illegal, and, thus, “any amount” of cannabis

“remains contraband,” id. at 99.24 The odor of cannabis, then,

“gives rise to probable cause to believe that the vehicle contains

contraband,” id., and the automobile exception authorizes a police

officer to search a vehicle based on probable cause that it contains

contraband, id. at 109.

The Court went even further, however, holding that, “separate

from the odor of [cannabis] providing probable cause to believe

that a vehicle contains contraband, the odor of [cannabis] provides

probable cause to believe that a vehicle contains evidence of a

crime.” Id. at 133 (emphasis added). Although this part of the

analysis was limited to just one paragraph in a long opinion, the

24

Although none of the defendants claimed that they possessed or

used cannabis for medical reasons, Robinson, 451 Md. at 97 n.2, the

Court acknowledged that qualifying patients and their caregivers who

comply with the State’s medical cannabis laws may not be subject to

arrest, prosecution, or any civil or administrative penalty for the

possession of cannabis, id. at 136 (discussing Md. Code Ann., Health-

Gen. § 13-3313(a)). Nonetheless, the Court repeatedly said that cannabis

“in any amount” remains contraband. Id. at 99, 125, 126, 129, 130, 137.

172 [107 Op. Att’y

Court reasoned that “[t]he odor of [cannabis] emanating from a

vehicle may be just as indicative of crimes such as the possession

of more than ten grams of [cannabis], possession of [cannabis] with

the intent to distribute, or the operation of a vehicle under the

influence of a controlled dangerous substance, as it is of possession

of less than ten grams of [cannabis].” Id. at 133-34. Thus, the

Court concluded, an officer who detects the odor of cannabis

emanating from a vehicle has probable cause to search that vehicle

based on the reasonable belief that the vehicle contains evidence of

a crime such as possession of 10 grams or more of cannabis,

distribution of cannabis, or driving under the influence of a

controlled dangerous substance. Id.

2. Searches of a Vehicle’s Occupants

In a series of cases after Robinson, the Court of Appeals

clarified that justification to search a vehicle does not necessarily

establish justification to search or pat down individuals inside that

vehicle. In one case, decided just two months after Robinson, the

Court of Appeals held that, while the odor of cannabis emanating

from a vehicle authorizes an officer to search that vehicle, the

officer needs more than the odor of cannabis to justify frisking the

occupants of that vehicle. Norman v State, 452 Md. 373, 379

(2017). As we noted above, see supra Part II.A.3.iii, a frisk must

be supported by reasonable suspicion that the person is armed and

dangerous. In Norman, an officer stopped a car with a broken

taillight and “detected a strong odor of fresh [cannabis] emanating

from the vehicle’s passenger compartment.” 452 Md. at 379-80.

The officer told the vehicle’s three occupants to get out of the car

so that he could search it for cannabis; the officer then frisked the

occupants to look for weapons and found, in one passenger’s front

pocket, a bag of cannabis. Id. at 380. In challenging the frisk, the

passenger argued that the officer lacked reasonable suspicion,

based solely on the odor of cannabis, that any of the vehicle’s

occupants were armed and dangerous. Id. at 384-85.

The Court held that the “odor of [cannabis] . . . emanating

from a vehicle with multiple occupants does not,” standing alone,

“give rise to reasonable articulable suspicion that the vehicle’s

occupants are armed and dangerous and subject to frisk.” Id. at

412. Instead, to justify frisking an occupant of the vehicle, an

officer must have “an additional circumstance or circumstances”

indicating that the occupant is armed and dangerous. Id. at 411. In

reaching this conclusion, the Court emphasized its prior holding in

Wallace that the odor of drugs emanating from a vehicle, without

more, does not provide probable cause to search the occupants of a

Gen. 153] 173

vehicle. Id. at 399. While acknowledging that “[a] frisk is different

from a search of a person,” id. at 388, the Court reasoned that both

types of seizures “involve applications of a defendant’s Fourth

Amendment right[] ‘to be secure in their person[ ], . . . against

unreasonable searches,’” a right that “can be violated by either an

unreasonable search or an unreasonable frisk.” Id. at 413 (quoting

U.S. Const. amend. IV). Whether an officer searches a person or

frisks them, the reasonableness of that action depends “on the

circumstances—or the lack of circumstances—that involve the

[person]” searched or frisked. Id. In short, “a law enforcement

officer cannot reasonably infer that a particular occupant of a

vehicle is armed and dangerous just because an odor of [cannabis]

indicates that [cannabis] may be somewhere in the vehicle.” Id. at

425; see also In re D.D., 479 Md. at 228 (“[W]hile the smell of

[cannabis] can justify a quick pat-down of a vehicle’s occupants if

combined with some other pertinent circumstance(s), the odor, in

and of itself, is insufficient to give rise to reasonable suspicion that

a specific individual within the vehicle is armed and dangerous.”).

In Pacheco, the Court of Appeals revisited the issue of

whether officers may arrest and search a vehicle’s occupants based

on the odor of cannabis. 465 Md. at 330. The Court there reiterated

that “the same facts and circumstances that justify a search of an

automobile do not necessarily justify an arrest and search incident

thereto.” Id. at 333. In Pacheco, two officers approached a vehicle

with its windows down, smelled burnt cannabis, and spotted a joint

in the center console. Id. at 318. One of the officers knew

immediately that the joint contained less than 10 grams of cannabis.

Id. Nonetheless, the officers ordered the driver, who was the sole

occupant, out of the vehicle and searched him, finding cocaine in

one of his front pockets. Id. The officers then searched the vehicle

and found a cannabis stem and two packets of rolling papers. Id.

The officers took the driver to a police station, where they issued

him a citation for possessing less than 10 grams of cannabis and

charged him with possession of cocaine with intent to distribute.

Id.

In court, the driver did not challenge the search of the vehicle

but argued that police had no authority to search his person. Id. at

318, 330. The Court of Appeals agreed, concluding that the

officers lacked probable cause to arrest (and, thus, search) the

driver based only on “their detection of ‘fresh burnt’ [cannabis]

emanating from the vehicle and the joint they observed in the center

console.” Id. at 332. Although courts will consider “the experience

and special knowledge of police officers,” id. (quoting Longshore

v. State, 399 Md. 486, 534 (2007)), the police in Pacheco did not

174 [107 Op. Att’y

point to any evidence indicating that, “in their experience and

training[,] the possession of one joint . . . supported an inference

that [the driver] also possessed roughly nine and a half more grams

of [cannabis] on his person,” id. at 332-33. And “[n]othing in the

record suggest[ed] . . . that [the driver] intended to distribute

[cannabis] or was operating the vehicle while under the influence

of [cannabis].” Id. at 332 n.7.25

3. Searches of Individuals Outside the Vehicle Context

In 2020, the Court of Appeals for the first time considered the

impact of decriminalization on an officer’s authority to search a

person, outside the vehicle context, based on the odor of cannabis.

Lewis v. State, 470 Md. 1 (2020). The Court in that case held that

“the odor of [cannabis], without more” no longer “provide[s] law

enforcement officers with the requisite probable cause to arrest and

perform a warrantless search of that person incident to arrest.” Id.

at 10. The Court reasoned that “police officers must have probable

cause to believe a person possesses a criminal amount of [cannabis]

in order to arrest that person and conduct a search incident thereto.”

Id. at 23. But, the Court explained, “[t]he odor of [cannabis] alone

is not indicative of the quantity (if any) of [cannabis] in someone’s

possession,” and, thus, does not indicate that a person has

committed a felony or a misdemeanor (as opposed to a civil

infraction or no infraction at all). Id.

Importantly, the Court in Lewis did not back away from its

reasoning in Robinson that “the odor of [cannabis] emanating from

a vehicle provides probable cause to believe that the vehicle

contains evidence of a crime.” Lewis, 470 Md. at 25 (quoting

Robinson, 451 Md. at 134) (emphasis added). But the Court

clarified that Robinson was limited to the vehicle context. In

explaining why the odor of cannabis provides probable cause to

search a vehicle but not to arrest a person, the Court in Lewis

contrasted the “diminished expectation of privacy one enjoys in

[their] vehicle” with the “heightened expectation of privacy

25

In a concurring opinion, Judge McDonald (joined by Judge Watts),

said that the majority opinion “should not be read to preclude a

conclusion that an officer has probable cause for arrest when the officer

comes upon an individual alone and awake in the driver’s seat of a

vehicle with a [cannabis] joint at hand and the pungent odor of [cannabis]

in the air.” Pacheco, 465 Md. at 337 (McDonald, J., concurring). But

to justify an arrest and search of that driver, an officer must be able to

point to other specific facts indicating that the driver has committed the

crime of driving while impaired by cannabis. Id.

Gen. 153] 175

enjoyed in one’s person.” Lewis, 470 Md. at 26. In particular, the

Court explained:

Arresting and searching a person, without a

warrant and based exclusively on the odor of

[cannabis] on that person’s body or breath, is

unreasonable and does violence to the

fundamental privacy expectation in one’s

body; the same concerns do not attend the

search of a vehicle.

Id. Thus, “more than the odor of [cannabis] is required for probable

cause to arrest a person and conduct a search incident thereto.” Id.

at 17.

The odor of cannabis does, however, permit a police officer

to briefly detain a person and investigate further. In a case decided

earlier this year, the Court of Appeals concluded that, “[e]ven

following partial decriminalization, the odor of [cannabis] on a

person provides reasonable suspicion to conduct a brief

investigatory detention to attempt to determine whether the person

has committed a criminal offense.” In re D.D., 479 Md. at 249.

That case involved the stop and frisk of D.D., a fifteen-year-old

boy, whom police encountered in an apartment building when

responding to a complaint about the odor of cannabis. Id. at 216.

The officers encountered D.D. and four friends, all smelling of

cannabis, and ordered them to sit down. Id.26

In upholding this stop, the Court of Appeals emphasized that

a stop requires only reasonable suspicion that criminal activity is

afoot, a standard “less stringent” than the probable cause required

to make an arrest. Id. at 230. Thus, “a particular circumstance or

set of circumstances” may “fall short of probable cause” but

“satisfy the reasonable suspicion standard.” Id. at 231. The Court

concluded that this is “precisely the case with respect to the odor

of [cannabis].” Id. According to the Court, “partial de-

criminalization has reduced the level of certainty associated with

the odor of [cannabis] on a person from probable cause that the

person has committed a crime to reasonable suspicion that the

person has committed a crime or is in the process of committing a

26

The Court recounted other facts surrounding the encounter as well,

such as the fact that no one in the group would tell the officers where

they lived, that all were wearing “baggy clothes,” and that the officers

found D.D. in particular “to be evasive.” Id. at 216, 218. But the

majority treated the case as one where the stop was justified by the smell

of cannabis alone. Id. at 241 n.10.

176 [107 Op. Att’y

crime.” Id. at 232. “Put another way, . . . the officers [here] could

not have arrested D.D. or any of the members of the group based

solely on the odor of [cannabis], but that does not mean the

officers’ suspicion that one or more of the group might possess at

least 10 grams of the drug—based on odor alone—was

unreasonable.” Id. at 235-36.

The Court rejected D.D.’s argument that, “[b]ecause the odor

of [cannabis] alone is not indicative of criminal activity and an

officer must have evidence of a crime in order to conduct an

investigatory stop, it necessarily follows that the odor of [cannabis]

alone does not provide reasonable suspicion to conduct a Terry

stop.” Id. at 224. In doing so, the Court emphasized that neither

probable cause nor reasonable suspicion requires police “to rule out

a suspect’s innocent explanation for suspicious facts.” Id. at 231

(quoting District of Columbia v. Wesby, 138 S. Ct. 577, 588

(2018)). And the Court further reasoned that, even though “there

are many wholly innocent reasons why someone might smell of

[cannabis],” “decriminalization has not rendered the odor of

[cannabis] free of all criminal suspicion . . . because the use or

possession of 10 grams or more of [cannabis] remains a criminal

offense in Maryland.” Id. at 231-32, 235; see also Robinson, 451

Md. at 133-34. In the Court’s view, “[t]here can be no real dispute

that the odor of [cannabis] still provides evidence of a crime . . .

even if it may not rise to the level of probable cause in every

situation.” In re D.D., 479 Md. at 235.

That the odor of cannabis would justify a stop but not

authorize an arrest also “makes sense,” the Court observed, “given

the differing levels of intrusiveness of the two Fourth Amendment

events” and the balance of interests involved. Id. at 232. While

“[a]n arrest is the ‘most intrusive encounter’ that a police officer

has with a citizen,” id. at 232-33 (quoting Swift v. State, 393 Md.

139, 150 (2006)), an investigatory detention is “limited in duration

and purpose and can only last as long as it takes a police officer to

confirm or to dispel his suspicions,” id. at 233 (quoting Swift, 393

Md. at 150). “Being stopped for a short amount of time so that an

officer can ask a few questions does not do the same ‘violence to

the fundamental privacy expectation in one’s body’ that being

placed in handcuffs and physically searched does.” Id. at 236.

Ultimately, in the Court’s view, “[t]he public interest in

investigating and prosecuting criminal offenses, balanced against

an individual’s freedom of movement and reasonable expectation

of privacy in their person,” justifies “a brief investigatory

detention” based on the odor of cannabis, but not an arrest. Id. at

233. “Indeed,” the Court observed, “it would be peculiar if the odor

Gen. 153] 177

of [cannabis] was sufficient to meet the higher standard of probable

cause needed to search a vehicle, but insufficient to meet the lower

standard of reasonable suspicion needed to briefly stop a person on

the street.” Id. at 236.

The Court further opined “that accepting D.D.’s argument

could significantly hamper the legitimate investigation of criminal

activity in Maryland.” Id. at 238. The Court noted that “[a]n

officer who lacks probable cause to arrest is not required ‘to simply

shrug his shoulders and allow a crime to occur or a criminal to

escape.’” Id. (quoting Adams v. Williams, 407 U.S. 143, 145

(1972)). But if reasonable suspicion required an officer to rule out

all innocent explanations of suspicious facts, an officer would not

be able to question someone with the butt of a handgun protruding

from their waistband (because some residents may lawfully carry a

firearm), or detain the driver of a car with potentially excessive

window tinting (because “inspection of a tinted window cannot

definitively tell whether the tint exceeds the legal limit”). Id. at

236-37. As to the odor of cannabis, the Court acknowledged that:

[w]hen a police officer smells [cannabis] on

someone, it is certainly the case that the

person may possess less than 10 grams of

[cannabis] or they may possess no [cannabis]

at all. But it also is possible that the person is

presently in possession of 10 or more grams

of [cannabis]. Under D.D.’s reasoning, police

officers would be powerless to conduct a brief

investigatory detention to try to determine

which category the person is in. That is not

what the Fourth Amendment requires. To the

contrary, the odor of [cannabis] permits an

officer to briefly detain an individual to

investigate whether that person has committed

a criminal offense.

Id. at 238.27

27

The Court further concluded that, based on the totality of the

circumstances, police had reasonable suspicion to frisk D.D. for a

weapon. In re D.D., 479 Md. at 243-44. Although the odor of cannabis

was one factor, the police also pointed to “the group’s ‘evasive body

language,’ and the fact that there were ‘five of them in baggy clothes’ in

a place ‘where they could run out the door.’” Id. “These circumstances,”

the Court concluded, “viewed collectively, would lead a reasonably

prudent law enforcement officer to suspect that D.D. was armed and

dangerous.” Id.

178 [107 Op. Att’y

Under the current decriminalization scheme, then, the odor of

cannabis emanating from a vehicle authorizes a police officer to

search that vehicle, whether it is the officer or a specially trained

dog who has detected the odor. The smell of cannabis in a vehicle

standing alone does not, however, authorize a search of the

vehicle’s occupants. And the smell of cannabis emanating from a

person, by itself, is no longer probable cause sufficient to justify an

arrest and search incident to arrest.28 But the odor of cannabis

coming from a person does provide sufficient reasonable

articulable suspicion to permit the officer to briefly detain that

person to investigate further, even without any other indication of

criminal activity.

D. Police Officers’ Likely Authority to Conduct Searches

Based on the Odor of Cannabis Once Some Use and

Possession of Cannabis Becomes Legal

Finally, we come to the question that the General Assembly

has asked us to answer: whether the legalization of the possession

of up to 1.5 ounces of cannabis will affect the authority of police

officers under the Fourth Amendment to conduct searches based on

the odor of cannabis.

Before offering our opinion, we pause for a moment to

address the role, if any, of the federal regulation of cannabis. More

specifically, does the fact that possession of any cannabis remains

a crime under federal law provide probable cause for a state’s

officers to search vehicles or individuals, regardless of the status of

cannabis under that state’s law? See, e.g., Kevin Cole, Probable

Cause to Believe What? Partial Marijuana Legalization and the

Role of State Law in Federal Constitutional Doctrine, 54 Crim. L.

Bull., Spring 2018, art. 1. There appears to be some uncertainty

about whether federal law offers a basis for state law enforcement

officers to conduct a search based on the odor of cannabis in a state

that has legalized or decriminalized its possession. See Orin S.

Kerr, Cross-Enforcement of the Fourth Amendment, 132 Harv. L.

Rev. 471, 475 (2018); compare Commonwealth v. Craan, 13

N.E.3d 569, 579 (Mass. 2014) (holding that, when state law

“expressly has decriminalized certain conduct, there is no extant

joint investigation, and the Federal government has indicated that

it will not prosecute certain conduct, the fact that such conduct is

technically subject to a Federal prohibition does not provide an

28

That does not mean, however, that the odor of cannabis could not

be one of several factors that establishes probable cause, which, of

course, depends on the totality of the circumstances. See, e.g., Pringle,

540 U.S. at 371.

Gen. 153] 179

independent justification for a warrantless search”), with United

States v. Sanders, 248 F. Supp. 3d 339, 347 (D.R.I. 2017) (finding

that the odor of cannabis contributed to an officer’s reasonable

suspicion because, “regardless of what the R.I. General Assembly

has declared” by decriminalizing the possession of less than one

ounce of the drug, “possession of [cannabis] is still unlawful under

federal law”).

The Maryland Court of Appeals has not addressed this precise

question. More than twenty-five years ago, in a case involving

handgun permitting laws, the Court of Appeals said that “state and

local law enforcement officials may appropriately enforce federal

law.” Department of Pub. Safety v. Berg, 342 Md. 126, 139 (1996).

The Court thus concluded that State Police could deny a handgun

permit to an applicant whose criminal history made him ineligible,

under federal law, to purchase a gun. Id. at 131-32, 139. But, as

far as we can tell, the Court has never decided whether it is

appropriate for a State police officer to rely on federal law to

establish probable cause for an arrest or a search.

That said, we think the Court of Appeals might have implicitly

decided the issue as applied to searches based on the odor of

cannabis.29 In Robinson, in which the Court held that the odor of

cannabis coming from a vehicle authorizes an officer to search that

vehicle, the Court noted that “[p]ossession of [cannabis] in any

amount . . . remains a crime under federal law.” 451 Md. at 97 n.1

(citing 21 U.S.C. § 844(a)). But the Court did not expressly rely

on this fact to support its holding, nor did the Court mention the

federal law in subsequent cases considering the effect of

Maryland’s decriminalization scheme. In fact, the Court later held

in Lewis that the Fourth Amendment did not permit officers to

arrest an individual (or conduct a search incident to arrest) based

solely on the odor of cannabis. While the Court did not expressly

consider in Lewis whether federal law might provide grounds for

the arrest, we assume that the Court did not forget that possession

of cannabis remains illegal under federal law. We thus infer that,

by holding in Lewis that the odor of cannabis on a person no longer

authorizes an arrest and search of that person, the Court implicitly

decided that a police officer in Maryland generally may not rely on

the fact that cannabis is illegal under federal law to justify an arrest

or search based solely on the odor of cannabis.30 Although we

29

We express no view on the topic in other contexts.

30

To be clear, there may be some circumstances under which

Maryland police officers are participating in joint investigations with

180 [107 Op. Att’y

cannot say with certainty how the courts would decide the question

if squarely presented, we assume for now that a Maryland officer

would not be able to rely on federal cannabis law to justify a search

(of either vehicles or persons) based on the odor of cannabis.

With that caveat, we begin our analysis of the General

Assembly’s questions by making clear that, once the use and

possession of cannabis under certain circumstances becomes legal,

the odor of cannabis will—at the very least—still be a factor that

officers may use to establish probable cause to conduct a search.

After all, “[t]he probable-cause standard . . . depends on the totality

of the circumstances,” Lewis, 470 Md. at 21 (quoting Pringle, 540

U.S. at 370-71), and “[a] factor that, by itself, may be entirely

neutral and innocent, can, when viewed in combination with other

circumstances, raise a legitimate suspicion in the mind of an

experienced officer,” Ransome v. State, 373 Md. 99, 105 (2003).

Thus, regardless of whether the odor of cannabis standing alone

will be enough to establish probable cause for a search, we believe

that the odor will, at the very least, still be a relevant factor in the

“flexible, all-things-considered approach” to assessing probable

cause. Florida v. Harris, 568 U.S. 237, 244 (2013); cf. Bailey v.

State, 412 Md. 349, 382 (2010) (“The odor of ether is an innocent

factor without context, but the totality of the circumstances may

lead to a conclusion that the lawful substance is associated with a

criminal purpose.”).

Indeed, courts in other states that have legalized some use and

possession of cannabis have held that the odor of cannabis is at

least a relevant factor in determining whether a police officer’s

search is justified. See Commonwealth v. Barr, 266 A.3d 25, 44

(Pa. 2021) (holding, in light of a state law legalizing possession and

use of cannabis for medical purposes, that “the odor of [cannabis]

alone does not amount to probable cause to conduct a warrantless

search of a vehicle but . . . may be considered as a factor in

examining the totality of the circumstances”); People v. Hill, 162

N.E.3d 260, 265 n.2 (Ill. 2020) (recognizing, in a state that had

legalized medical cannabis use, “the smell and presence of

cannabis undoubtedly remains a factor in a probable cause

determination”); People v. Zuniga, 372 P.3d 1052, 1054 (Colo.

2016) (holding, since passage of a state constitutional amendment

legalizing some use and possession of cannabis, that “the odor of

federal officers, see, e.g., Md. Code Ann., Pub. Safety (“PS”) § 2-

412(c)(12), or are deputized to act on behalf of the federal government,

see, e.g., 21 U.S.C. § 878; PS § 2-412(d). We do not consider here how

those situations might affect a Maryland officer’s authority to rely on

federal law in conducting a search based on the odor of cannabis.

Gen. 153] 181

[cannabis] is relevant to the totality of the circumstances test and

can contribute to a probable cause determination”).

The more difficult questions are whether, when some use and

possession of cannabis becomes legal in Maryland, the odor of

cannabis standing alone will be enough to justify a police officer’s

search of a vehicle or a police officer’s investigatory stop of an

individual. Cf. Zuniga, 372 P.3d at 1060 n.6 (declining to decide,

after Colorado legalized possession of recreational cannabis,

whether the odor of cannabis alone would support probable cause

to search a vehicle). Obviously, even though the Maryland courts

have held that the odor of cannabis alone could support vehicle

searches and investigatory stops under the State’s

decriminalization regime, the fact that some amount of cannabis

will, beginning July 1, 2023, be fully legal to possess under State

law raises new questions about whether the odor of cannabis, by

itself, justifies those actions.

Before offering our opinion as to what Maryland’s appellate

courts would decide, we emphasize that we are not writing on a

blank slate. The Court of Appeals has already analyzed how the

State’s shift to decriminalization has affected the authority of

officers to conduct searches and to make arrests based on the odor

of cannabis standing alone. Our task here is to predict as best as

we can, based on that body of precedent, how the Court of Appeals

would rule, regardless of how we might have approached the

question on a blank slate. With that understanding of our role, we

turn to the General Assembly’s questions.

1. Searches of Vehicles and Their Occupants

We first consider whether, when possession of up to 1.5

ounces of cannabis becomes legal, officers will still have probable

cause under the automobile exception to search a vehicle based on

the odor of cannabis standing alone.31

In our view, although not entirely clear, the Court’s reasoning

in Robinson suggests that the Court would conclude that the odor

of cannabis coming from a vehicle, standing alone, still justifies a

warrantless search of the vehicle under the impending partial

legalization scheme, on the ground that it will still provide an

31

The Court of Appeals acknowledged in In re D.D. that voters would

decide during the November 2022 election whether to approve the

legalization of some use and possession of cannabis, but the Court

declined to offer any opinion as to legalization’s potential impact on the

Court’s Fourth Amendment jurisprudence. 479 Md. at 232 n.6.

182 [107 Op. Att’y

officer with probable cause to believe that the vehicle contains

evidence of a crime. Robinson, 451 Md. at 133-34. We recognize

that the Court’s opinion in Robinson was “based largely on the

idea” that, under the State’s decriminalization regime, possession

of cannabis in any amount remains illegal (and, thus, contraband),

In re D.D., 479 Md. at 226—a rationale that will no longer apply

after the partial legalization of cannabis. The Court also repeatedly

emphasized in its opinion that “decriminalization is not . . .

legalization.” Robinson, 451 Md. at 99, 125.

But, although the Court in Robinson focused on the fact that

cannabis in any amount remains contraband under the State’s

decriminalization regime, the Court also relied on a second,

“separate” rationale: that the odor of cannabis emanating from a

vehicle “provides probable cause to believe that [the] vehicle

contains evidence of a crime.” Id. at 133. While acknowledging

that the odor may be indicative of the non-criminal activity of

“possession of less than ten grams of [cannabis],” the Court

concluded that the odor was “just as indicative of crimes such as

the possession of more than ten grams of [cannabis], possession of

[cannabis] with the intent to distribute, or the operation of a vehicle

under the influence of a controlled dangerous substance.” Id. at

133-34 (emphasis added). Although this “separate” rationale was

discussed in only one paragraph of the Court’s decision in

Robinson, the Court has repeatedly reaffirmed that view in its later

decisions. See Pacheco, 465 Md. at 328-29 (quoting Robinson, 451

Md. at 134); Lewis, 470 Md. at 25 (same); In re D.D., 479 Md. at

226-27 (quoting Robinson, 451 Md. at 133-34).

That separate rationale is important because Maryland’s

impending legalization scheme does not provide for full

legalization. Even under that partial legalization scheme, some

amounts of cannabis will remain illegal to possess: an amount

greater than 1.5 ounces but less than 2.5 ounces will be subject to

civil penalties, and possession of 2.5 ounces or more will be subject

to criminal penalties. 2022 Md. Laws, ch. 26, § 4 (amending CL

§§ 5-101, 5-601). Indeed, the crimes mentioned in Robinson as

providing probable cause to search a vehicle based on the odor of

cannabis will all remain crimes under the proposed partial

legalization scheme, though the amount of cannabis necessary to

trigger criminal penalties for simple possession will increase from

10 grams (about 0.35 ounces) to 2.5 ounces (about 71 grams). See

supra at 158-59 & nn.9, 11. While this new amount will be about

seven times greater than the current criminal amount, 2.5 ounces is

Gen. 153] 183

not so much that it could not be concealed in a vehicle.32 And the

Court’s observation that the odor of the drug can indicate criminal

activity will remain true, even once the criminal amount of

cannabis increases from 10 grams to 2.5 ounces.

We acknowledge, of course, that probable cause “deal[s] with

probabilities.” Gates, 462 U.S. at 231. As a matter of common

sense, we expect that an increase in the amount of cannabis

necessary to trigger criminal penalties will lead to an increase in

the number of people lawfully possessing and using cannabis. If

so, the level of probability that the odor of cannabis connotes the

possession of a criminal amount of cannabis will likely diminish.

Indeed, the Court of Appeals itself has recognized (in the context

of the odor of cannabis on a person) that a change in the drug’s

legal status can reduce the certainty that the odor is associated with

a crime. See In re D.D., 479 Md. at 232 (concluding that “partial

decriminalization has reduced the level of certainty associated with

the odor of [cannabis] on a person from probable cause that the

person has committed a crime to reasonable suspicion that the

person has committed a crime or is in the process of committing a

crime”).

But, even if the smell of cannabis becomes less indicative than

before of the possession of a criminal amount of cannabis, probable

cause does not require an officer to establish by a preponderance of

the evidence that the car contains evidence of a crime. Freeman,

249 Md. App. at 301-02. Probable cause in this context requires

only a “fair probability” that evidence of a crime is present,

Robinson, 451 Md. at 109 (quoting Harris, 568 U.S. at 244), not

that the odor of cannabis is more likely associated with criminal

rather than non-criminal activity.

More importantly, the Court of Appeals has also identified

other crimes, besides simple possession, that are associated with

the odor of cannabis in vehicles: driving while impaired by

cannabis and “crimes involving the distribution of [cannabis],”

such as possession of cannabis with the intent to distribute.

Robinson, 451 Md. at 133-34. In other words, even if the

possibility that the car might contain evidence of one of these

crimes would be insufficient on its own to rise to the level of

probable cause, the combined probability that the car contains

evidence of at least one of those crimes might provide an officer

32

An ounce of cannabis, sometimes referred to as a “zip of weed,”

“usually fits comfortably into” a Ziploc bag. Will Vance, A Zip of Weed:

What the Heck Is It and How Much Does It Cost?, Magnetic Magazine

(Sept. 8, 2022), https://www.magneticmag.com/2022/09/zip-of-weed/.

184 [107 Op. Att’y

with probable cause. And if legalization increases the number of

people who possess and use the drug, one might reasonably expect

an increase in the incidence of driving while impaired by cannabis.

See, e.g., National Highway Traffic Safety Admin., Marijuana-

Impaired Driving: A Report to Congress 17 (2017).33 Similarly,

because the impending legalization scheme does not yet include a

legal marketplace for buying and selling recreational cannabis in

Maryland, we cannot say that incidents of unlawful distribution of

cannabis and the possession of cannabis with intent to distribute are

likely to diminish.

In fact, in the absence of a legal marketplace for recreational

cannabis, the odor of cannabis coming from a vehicle will

presumably still be highly indicative that the car may contain

evidence of unlawful distribution, even if the dealer is not among

the vehicle’s occupants.34 After all, to lawfully search a vehicle

under the Fourth Amendment, an officer need not suspect an

occupant of criminal activity; the officer need only have probable

cause to believe that the vehicle contains contraband or evidence of

a crime. See, e.g., Harris, 568 U.S. at 243; see also Zurcher v.

Stanford Daily, 436 U.S. 547, 556 (1978) (“The critical element in

a reasonable search [of property] is not that the owner of the

property is suspected of crime but that there is reasonable cause to

believe that the specific ‘things’ to be searched for and seized are

located on the property to which entry is sought.”); Wyoming v.

Houghton, 526 U.S. 295, 302 (1999) (recognizing that this

principle applies to warrantless searches of automobiles); 2 Wayne

R. LaFave, Search & Seizure: A Treatise on the Fourth Amendment

33

We acknowledge that, in cases of suspected drunk driving, the odor

of alcohol may establish reasonable suspicion of impaired driving but

not probable cause to search a vehicle. See, e.g., Ferris v. State, 355 Md.

356, 391 (1999) (“Bloodshot eyes, in conjunction with the odor of

alcohol emanating from the person, would ordinarily provide the police

with reasonable suspicion that a driver was under the influence of

alcohol.”). But, unlike cannabis, there is no amount of alcohol that is

illegal for adults to possess. Moreover, there is no crime of possession

of alcohol with intent to distribute. Thus, the odor of alcohol alone does

not raise the same overall level of suspicion of contraband or criminal

activity as does the odor of cannabis.

34

We do not mean to suggest that, beginning July 1, 2023, everyone

in possession of recreational cannabis in Maryland will necessarily have

purchased it from an illegal dealer in the State; some people will have

grown it themselves or have purchased it in another jurisdiction with a

legal marketplace for recreational cannabis. But, again, probable cause

does not require a more-than-fifty-percent likelihood that evidence of a

crime would be found, only a “fair probability.” Gates, 462 U.S. at 238.

Gen. 153] 185

§ 3.1(b) (6th ed. 2020) (recognizing that “probable cause to search

a particular place may exist without there also being probable cause

to arrest a person who occupies that place,” and “there can be

probable cause to search a vehicle without there also being

probable cause to arrest the owner or operator of that vehicle”).35

Thus, at least until the State has established a legal marketplace for

cannabis, the odor of cannabis will still suggest that the car may

contain evidence of the crime of illegal distribution.36

We acknowledge that some courts in other states have

concluded that the odor of cannabis cannot, without more, establish

the requisite probable cause when at least some use and possession

of the drug is no longer subject to criminal or civil penalties. For

example, in Pennsylvania, after lawmakers legalized the possession

and use of cannabis for medical purposes, the state supreme court

concluded that the odor of cannabis “alone cannot create probable

cause to justify a search” of a vehicle. Barr, 266 A.3d at 28, 41.

The court reasoned that a “lawful activity cannot alone be the basis

for probable cause,” and “it is simply not a crime for an individual

to possess or use [cannabis] if the requirements of” the state’s

medical cannabis statute “have been satisfied.” Id. at 43. “Thus,”

the court concluded, “one’s liberty may not be abridged on the sole

basis that a law enforcement officer detected the smell of

[cannabis], because, to do so, would eliminate individualized

suspicion required for probable cause and would misapply the

totality-of-the-circumstances test.” Id.37

35

In addition to the possibility that the car will contain evidence of

one of the crimes listed in Robinson, there is also still at least some

additional possibility that the odor of cannabis is indicative of the

possession of contraband, even if the amount is not criminal to possess.

Under the revised statute, possession of an amount greater than 1.5

ounces but less than 2.5 ounces would be a civil violation and that

cannabis would thus be contraband. That possibility is surely not enough,

on its own, to justify a search of the vehicle but it adds to the overall

possibility that the vehicle contains contraband or evidence of a crime.

36

We need not decide here whether the same would be true once

Maryland has established a legal marketplace for the sale of cannabis,

though—even then—cannabis will remain evidence of a crime under

many circumstances.

37

In Michigan, another state that has enacted a statute legalizing

cannabis use for medical purposes, the intermediate appellate court has

said that the odor of burnt cannabis, standing alone, can still establish

probable cause to search a vehicle that is in a public place, because the

statute does not permit the use of cannabis in public. See People v.

Anthony, 932 N.W.2d 202, 206-07, 213, 215 (Mich. Ct. App. 2019)

186 [107 Op. Att’y

Similarly, the intermediate appellate court of Illinois, where

an adult may now legally possess up to 30 grams of cannabis,

recently held that “the smell of . . . burnt cannabis, without any

corroborating factors, is not enough to establish probable cause to

search [a] vehicle.” People v. Stribling, __ N.E.3d __, 2022 WL

4299289, at *4, *6 (Ill. App. Ct. Sept. 19, 2022). In that case, an

officer smelled the odor of burnt cannabis emanating from a

vehicle, and the driver said that “someone (he did not state that it

was himself) had smoked in the vehicle ‘a long time ago.’” Id. at

*5. Finding this evidence insufficient to establish probable cause

to search the vehicle, the court observed that, given the state’s

decision to legalize possession of some amount of cannabis, the

smell of cannabis alone would no longer “lead a reasonable officer

to conclude that there was a substantial chance of criminal activity

afoot.” Id. The Court of Appeals of Oregon also reached a similar

conclusion, under a provision of the Oregon Constitution which

permits a police officer to extend a traffic stop “to conduct a

criminal investigation” unrelated to the “purpose of the traffic stop”

if the officer has “reasonable suspicion of criminal activity.” State

v. Moore, 488 P.3d 816, 819 (Or. 2021) (discussing Or. Const., Art.

I, § 9). The Oregon court held that, because “the possession and

transport of [cannabis], in a variety of amounts and forms, is now

legal” in the state, even a “very strong odor” of cannabis is “not a

specific enough articulation to adequately support reasonable

suspicion that [cannabis] [is] therefore present in [a] vehicle in an

unlawful quantity.” Id. at 819-21. Given that “reasonable suspicion”

is a lower standard than probable cause, that reasoning suggests

that the Oregon court would find that the odor of cannabis no longer

provides probable cause to search a vehicle under the Fourth

Amendment.38

(involving an officer who smelled the odor of burnt cannabis coming

from a vehicle parked on a public street). But the court has said that the

odor of fresh (i.e., unburnt) cannabis does not, standing alone, permit a

warrantless search of a vehicle, without some “basis to believe that a

suspect’s actions, i.e., the use or possession of the [cannabis], fall outside

the protections of the” statute. See People v. Moorman, 952 N.W.2d 597,

601-02 (Mich. Ct. App. 2020) (per curiam) (finding that an officer had

probable cause to search a vehicle based on the odor of fresh cannabis

and the driver’s denial that the vehicle contained any cannabis, because

the denial was “inconsistent with [the officer’s] testimony that he

smelled the odor of fresh [cannabis]” and, thus, suggested that the vehicle

contained an amount greater than that allowed under the statute).

38

Other courts have said that merely decriminalizing some use and

possession of cannabis means that the odor of the drug, standing alone,

no longer establishes probable cause to search a vehicle. In a series of

Gen. 153] 187

As the above discussion demonstrates, those courts that have

concluded that the odor of cannabis no longer provides probable

cause for a search have grounded their decisions in the fact that the

odor will often be associated with noncriminal activity. But our

Court of Appeals has so far departed from this line of thinking,

concluding instead that, because the odor of cannabis is “just as

indicative” of criminal activity as noncriminal activity, it is

reasonable to permit an officer to conduct a search of a vehicle that

smells of cannabis. Robinson, 451 Md. at 133-34. Indeed, the

Court expressly declined to follow the Massachusetts high court’s

decision in Overmyer (which had found the odor of cannabis to be

insufficient to provide probable cause even under a

decriminalization regime), noting that such a conclusion would

have “the effect of precluding all warrantless searches of vehicles

based on the odor of [cannabis], which would not be a salutary

development in Maryland.” Id. at 133.39

cases decided under a then-existing decriminalization scheme, the

Supreme Judicial Court of Massachusetts concluded that “a warrantless

search is not justified based solely on the smell of [cannabis], whether

burnt or unburnt,” Commonwealth v. Overmyer, 11 N.E.3d 1054, 1059-

60 (Mass. 2014), because an officer must suspect “criminal, as opposed

to merely infractionary, conduct,” Commonwealth v. Cruz, 945 N.E.2d

899, 908-09 (Mass. 2011), and “a human nose can[not] discern reliably

the presence of a criminal amount of [cannabis], as distinct from an

amount subject only to a civil fine,” Overmyer, 11 N.E.3d at 1059.

Likewise, the Supreme Court of New Hampshire held that, under a

decriminalization scheme, the odor of cannabis emanating from a

vehicle, standing alone, no longer supports even “reasonable, articulable

suspicion that a person possesses an illegal quantity of marijuana.” State

v. Perez, 239 A.3d 975, 980, 986 (N.H. 2020). The New Hampshire

court reasoned that “the odor of marijuana may indicate both criminal

and non-criminal activity,” id. at 984, and “the case-by-case nature of the

reasonable, articulable suspicion analysis counsels against a per se rule,”

id. at 986. Obviously, those courts would come to the same conclusion

under a legalization scheme.

39

We think it likely that our Court of Appeals would also find the

Pennsylvania Supreme Court’s decision in Barr, which was decided four

years after Robinson, unpersuasive. As noted above, the Barr Court

concluded that legalization of cannabis only for medical purposes

rendered the odor of cannabis, standing alone, insufficient to establish

probable cause to justify a search. Barr, 266 A.3d at 28, 41. But that

conclusion clashes with Robinson, which held that the odor of cannabis

still provides probable cause for a search in Maryland, notwithstanding

the fact that Maryland law already permitted possession and use of

cannabis for medical purposes. See Robinson, 451 Md. at 135-37

(recognizing “the ability of eligible persons to possess and/or use

[cannabis] for medical purposes,” but making no mention of that fact in

its analysis of the probable cause issue).

188 [107 Op. Att’y

To be sure, the Court of Appeals may ultimately decide that,

after partial legalization takes effect, a search based solely on the

odor of cannabis is no longer “reasonable”—the touchstone of

Fourth Amendment law. That is, the Court could conclude that the

partial legalization of cannabis, given that it changes the default

treatment of recreational cannabis under Maryland law, is

sufficiently different from decriminalization to justify a different

result. But, although the Court might ultimately decide the

reasoning in Robinson should no longer apply, that is for the Court,

not for us, to decide. In the meantime, we must faithfully adhere

to the logic of that decision. In doing so, we note that the Court

expressed concern that prohibiting officers from “conduct[ing]

warrantless searches of vehicles based on the odor of [cannabis]”

“would permit a myriad of crimes to go undetected.” Id. The

Court’s analysis also emphasized that “[w]hether a search is

reasonable depends on the public interest versus an individual’s

right to be free from arbitrary interference” by police. Id. at 108.

And as the Court explained in subsequent decisions, the search of

a vehicle does not raise the same fundamental privacy concerns as

the arrest and search of a person, Lewis, 470 Md. at 26, because of

the “diminished expectation of privacy one has in an automobile,”

In re D.D., 479 Md. at 228.

The foregoing leads us to believe that, under the impending

partial legalization scheme, the Court of Appeals would still likely

consider the odor of cannabis, standing alone, sufficient to establish

probable cause to search a vehicle, at least until the General

Assembly has established a legal marketplace for the sale of

cannabis and possibly even afterwards. Although it is possible that

the Court could conclude that the certainty associated with the odor

of cannabis emanating from a car will diminish from probable

cause to mere reasonable suspicion, cf. In re D.D., 479 Md. at 232

(concluding the same with respect to decriminalization’s effect on

the odor of cannabis emanating from a person), we cannot say that

with confidence. The Court has repeatedly emphasized the

diminished expectation of privacy in vehicles as compared to

persons, e.g., Lewis, 470 Md. at 26, and has shown reluctance to

preclude all warrantless searches of vehicles based on the odor of

cannabis, Robinson, 451 Md. at 132-33. Moreover, vehicles could

be used by impaired drivers and could easily conceal a criminal

amount of cannabis or evidence of illegal distribution or possession

of the drug with the intent to distribute it. Collectively, these

factors lead us to believe that, under the impending partial

legalization scheme, the Court of Appeals would more likely still

hold that the odor of cannabis, standing alone, establishes probable

cause to search a vehicle.

Gen. 153] 189

We hasten to add that the certainty of our opinion is limited

by the relative lack of legal authority addressing the effect that

partial legalization of cannabis has had on officers’ authority to

conduct searches based on the odor of cannabis. We also lack a

firm idea, from either the legislative history of the 2022 cannabis

bills or the public record, of how many Marylanders will likely

possess and use cannabis under the impending legalization scheme,

how common the odor of cannabis in vehicles might be as a result,

and exactly how indicative that odor will be of criminal activity. In

addition, the fact that the use of medical cannabis and hemp are

legal under certain circumstances could also impact the

reasonableness of an officer’s belief that the odor of cannabis (or

what seems to be cannabis40) is indicative of criminality. But none

of the Court of Appeals decisions thus far have addressed the

impact, if any, that medical cannabis or hemp may have on this

question.

In short, our opinion is simply our best effort to predict how

the Court of Appeals would rule in an area of the law that remains

highly uncertain. Given this uncertainty, police officers should be

aware that there is some risk that a court might suppress evidence

that an officer obtained in a search of a vehicle based solely on the

odor of cannabis.

That said, the Legislature does have some authority to resolve

this uncertainty. While the General Assembly cannot legislate

what the Fourth Amendment permits, a state does have “power to

impose higher standards on searches and seizures than required by

the Federal Constitution if it chooses to do so.” Cooper v.

California, 386 U.S. 58, 62 (1967). Several other states have

40

As noted above, hemp is legal and distinct from cannabis, but some

criminal defendants have argued that the odor of cannabis is

indistinguishable from that of hemp. See, e.g., State v. Teague, __ S.E.2d

__, 2022 WL 16558096, at *3 (N.C. Ct. App. 2022); Gowen v. State, 860

S.E.2d 828, 831 (Ga. Ct. App. 2021). We are aware of only two

Maryland cases in which a defendant made this argument on appeal. In

the first case, the Court of Special Appeals concluded in an unreported

decision that the record did not establish “that [cannabis] and hemp emit

identical odors such that an officer cannot distinguish between them.”

Hall v. State, No. 1355, Sept. Term, 2021, 2022 WL 4243950, at *4 (Md.

Ct. Spec. App. Sept. 15, 2022). We are, of course, not equipped to

resolve those sorts of factual questions in our advisory opinions. In the

second case, the intermediate appellate court held in an unreported

decision that, under Robinson, an officer had probable cause to search a

vehicle based on what he perceived to be the odor of cannabis. Jerome

v. State, No. 1855, Sept. Term, 2021, 2022 WL 17337634, at *1 (Md. Ct.

Spec. App. Nov. 30, 2022) (per curiam).

190 [107 Op. Att’y

enacted legislation prohibiting or limiting police from conducting

searches based on the odor of cannabis.41 But absent similar

legislation in Maryland, it is our opinion that, under the impending

legalization scheme, police will likely still have the authority to

conduct searches of vehicles based solely on the odor of cannabis.

Like under current law, however, the odor of cannabis coming

from a vehicle will not, standing alone, permit police to search the

vehicle’s occupants. The Court of Appeals has already made clear

that officers must be able to point to something more to justify the

arrest and search of an occupant. Pacheco, 465 Md. at 332.

Legalization of some possession and use of cannabis will not

disrupt that holding.

As a side note, we think it will make no difference to our

analysis whether an officer detects the odor of burnt cannabis or

the odor of fresh (i.e., unburnt) cannabis. Although there is some

authority outside Maryland that “the odor of unburnt, rather than

burnt, [cannabis] could be more consistent with the presence of

larger quantities,”42 and that the odor of burnt cannabis is more

consistent with driving under the influence of the drug,43 the Court

of Appeals has, so far at least, not attributed any special

significance to whether an officer smelled fresh or burnt cannabis

when the Court has affirmed the authority of police to conduct

vehicle searches based solely on the odor of cannabis. Compare

41

See, e.g., Conn. Gen. Stat. Ann. § 54-33p; N.J. Stat. Ann. § 2C:35-

10c; N.Y. Penal Law § 222.05(3), (4); Va. Code Ann. § 4.1-1302. In

California, where individuals 21 and older may possess and use up to

28.5 grams of cannabis, the legislature has not explicitly said that the

odor of cannabis may not establish probable cause to search a vehicle.

But lawmakers have said that “[c]annabis and cannabis products

involved in any way with conduct deemed lawful by [statute] are not

contraband nor subject to seizure, and no conduct deemed lawful by

[statute] shall constitute the basis for detention, search, or arrest.” Cal.

Health & Safety Code § 11362.1(a), (c). A California appellate court has

said that this statute “definitively affects probable cause determinations”

and “undercuts the continued viability of” an earlier case that held “that

the odor of marijuana alone establishes probable cause.” People v.

Johnson, 264 Cal. Rptr. 3d 103, 110-11 (Cal. Ct. App. 2020).

42

Overmyer, 11 N.E.3d at 1058 (but going on to say that “it does not

follow that such an odor reliably predicts the presence of a criminal amount

of the substance”); see also Zullo v. State, 205 A.3d 466, 502 (Vt. 2019)

(asserting that “the faint smell of burnt [cannabis] is far less probative as to

whether a car contains [cannabis] than, say, an overpowering odor of fresh

[cannabis] emanating from the trunk of a car”).

43

State v. Bowen, 481 P.3d 370, 374 (Or. Ct. App. 2021).

Gen. 153] 191

Robinson, 451 Md. at 99-106 (holding that officers’ detection of a

strong odor of “fresh” (i.e., unburnt) cannabis coming from

vehicles authorized the search of those vehicles), with, e.g.,

Pacheco, 465 Md. at 318, 330 (recognizing, in a case involving a

vehicle that smelled of burnt cannabis, that the odor permitted a

search of the vehicle but not, without more, the vehicle’s driver).

Finally, although this issue was not specifically mentioned in

the Legislature’s opinion request, we also note that the impending

legalization scheme calls into question the ability of officers to

obtain the necessary probable cause to search a vehicle by using

dogs trained to detect the odor of cannabis. It is clearly not a

“search” under the Fourth Amendment for officers to use their own

noses to smell cannabis emanating from a car, because a person has

no reasonable expectation of privacy in odors that waft into a public

space, such as a highway, where an officer (or any other person)

could smell them. See supra footnote 20. But a dog’s sense of

smell is more than 100,000 times stronger than a human’s, see

Reid, supra, at 183, allowing a dog to detect odors that may be

imperceptible to a person and thus raising different questions about

whether a dog sniff intrudes on reasonable expectations of privacy

and thereby constitutes a search.

Although (as explained above) the Supreme Court has

historically concluded that a dog’s sniff is generally not a “search”

under the Fourth Amendment—despite the fact that other sense-

enhancing techniques can sometimes constitute a search for which

probable cause is required, cf. Kyllo, 533 U.S. at 34-35—the

Court’s rationale for that conclusion may be undermined by the

partial legalization of cannabis. More specifically, the Supreme

Court has said up to this point that dog sniffs generally are not

searches because no one has a legitimate expectation of privacy in

contraband and trained dogs historically have been used to alert

only to the presence or absence of contraband. Place, 462 U.S. at

707.44 But, once Maryland’s partial legalization scheme takes effect

44

See also Andreas, 463 U.S. at 771 (recognizing that a “search”

occurs only when a government inspection “intrude[s] upon a legitimate

expectation of privacy”); Caballes, 543 U.S. at 409 (concluding that “the

use of a well-trained narcotics-detection dog—one that ‘does not expose

noncontraband items that otherwise would remain hidden from public

view’— . . . generally does not implicate legitimate privacy interests”)

(emphasis added) (quoting Place, 462 U.S. at 707); 1 Wayne R. LaFave,

Search and Seizure: A Treatise on the Fourth Amendment § 2.2(g) (6th

ed. 2020) (noting “the unique nature of the investigative technique” of

using canines, whose sniff can “disclose[] only criminality and nothing

192 [107 Op. Att’y

and cannabis in Maryland is no longer contraband in every instance,

it will no longer always be true that a dog’s sniff will be able to detect

only the presence or absence of contraband, as even a specially

trained dog cannot tell whether it is smelling a quantity of cannabis

that is greater or less than 1.5 ounces. See, e.g., Denise LaVoie, Since

the Nose Doesn’t Know Pot Is Now Legal, K-9s Retire, Associated Press,

May 29, 2021, https://apnews.com/article/va-state-wire-police-marijuana-

marijuana-legalization-253af1ba6e541060085108e027b367c1 (reporting

that police departments in states that have legalized cannabis have

retired cannabis-detecting dogs because they “cannot distinguish

between a small, legal amount of [cannabis] or a larger, still-illegal

amount of the drug”); see also Douglas A. Berman & Alex Kreit,

Ensuring Marijuana Reform Is Effective Criminal Justice Reform,

52 Ariz. St. L.J. 741, 765-66 (2020) (arguing that, “once [cannabis]

is no longer considered contraband, the police may no longer be

permitted to conduct suspicionless drug dog sniffs using dogs that

are trained to detect [cannabis]”). Because such a dog could alert

to “noncontraband items” (i.e., lawful amounts of cannabis) “that

otherwise would remain hidden from public view,” a dog’s sniff

under those circumstances appears to “implicate legitimate privacy

interests.” Caballes, 543 U.S. at 409.

Thus, based on existing Supreme Court precedent, there is a

significant risk that Maryland’s appellate courts would conclude

that a dog sniff for cannabis is a search. See Andreas, 463 U.S. at

771; see also Maryland v. Macon, 472 U.S. 463, 469 (1985) (“A

search occurs when ‘an expectation of privacy that society is

prepared to consider reasonable is infringed.’” (quoting United

States v. Jacobsen, 466 U.S. 109, 113 (1984))); People v.

McKnight, 446 P.3d 397, 408-10 (Colo. 2019) (holding that a dog

sniff is a search that must be supported by probable cause under

Colorado law because “persons twenty-one or older may lawfully

possess [cannabis] in small amounts” in Colorado and, thus, “a

drug-detection dog that alerts to even the slightest amount of

marijuana can no longer be said to detect ‘only’ contraband”); Alex

C. Carroll, Weed, Dogs & Traffic Stops, 21 Wyo. L. Rev. 1, 6

(2021) (arguing that “a dog sniff conducted during a routine traffic

stop is a Fourth Amendment ‘search’ in states that have legalized

marijuana”). And if a dog sniff indeed amounts to a “search” for

constitutional purposes under these circumstances, the officer

would have to establish probable cause before allowing the dog to

sniff the vehicle, as opposed to using the dog sniff to establish

else”); Reid, supra, at 183 (noting that, “if a dog is . . . trained to detect

ONLY the presence of odor emanating from an illegal substance, then

the dog, when it alerts, is detecting a substance that no one has a lawful

reason to possess”).

Gen. 153] 193

probable cause to search the vehicle.45 Again, this is a novel area

of the law, and the doctrine could potentially evolve. All we can

do for the time being is provide our best advice based on how

current precedent might apply to these new circumstances. But

police departments need to be aware that the impending

legalization regime may change the way that drug-sniffing dogs—

at least those trained to detect cannabis—are viewed under the

Fourth Amendment.

2. Searches of Individuals Outside the Vehicle Context

We next consider whether Maryland’s impending legalization

scheme will affect the authority of police officers to search

individuals based on the odor of cannabis outside of the vehicle

context. The Court of Appeals has already held that police cannot,

even under current law, arrest and search a person merely because

the person smells of cannabis. Lewis, 470 Md. at 17, 23. In that

context, unlike with vehicle searches, the police need probable

cause to believe that the specific person being arrested has

committed a felony or is committing a crime in the officer’s

presence, and the search involves a greater intrusion of privacy than

the search of a vehicle. E.g., id. at 20, 22, 25-26.

In our view, this limitation on searches of persons incident to

arrest will remain true once it becomes legal for someone who is at

least 21 years old to possess up to 1.5 ounces. Under that scheme,

the reasoning of Lewis will still apply: Because “[t]he odor

of [cannabis] alone is not indicative of the quantity (if any) of

[cannabis] in someone’s possession,” id. at 23, officers will not be

able to know whether the scent is associated with a crime or with

the lawful use or possession of cannabis; thus, “[a]rresting and

45

It is possible, of course, that an officer could encounter a vehicle

occupied only by a driver whom the officer knows to be under 21 and,

thus, not entitled to possess any amount of cannabis; in that case, a dog’s

sniff for cannabis will still detect only the presence or absence of

contraband and thus would almost certainly not give rise to a

constitutional search under the logic of current precedent. In addition, it

is clear that police could still, even without first establishing probable

cause, use a canine trained to detect only those drugs that are illegal in

any quantity (such as heroin or cocaine), although that approach would

presumably require police departments to re-train police dogs or train

new dogs so that they do not alert to the odor of cannabis. See

Reid, supra, at 208 (asserting that “[l]aw enforcement dog handlers will

be the most affected by” the legalization of cannabis, and “police

departments . . . will have to train new drug dogs to detect the usual illegal

substances, such as heroin, cocaine, and methamphetamine, but exclude

the odor of [cannabis]”).

194 [107 Op. Att’y

searching a person, without a warrant and based exclusively on the

odor of [cannabis] on that person’s body or breath, [will be]

unreasonable and [will] do[] violence to the fundamental privacy

expectation in one’s body,” id. at 26. If, however, other facts

arouse an officer’s suspicions, the odor of cannabis can be

considered among the totality of circumstances in determining

whether there is probable cause to arrest. See id. at 21; Ransome,

373 Md. at 105.

Less certain is whether the Court of Appeals would still

permit brief investigatory stops based solely on the odor of

cannabis coming from a person. The Court of Appeals, in its recent

decision about investigatory stops under the current

decriminalization regime, said that “partial decriminalization has

reduced the level of certainty associated with the odor of [cannabis]

on a person from probable cause that the person has committed a

crime to reasonable suspicion that the person has committed a

crime or is in the process of committing a crime.” In re D.D., 479

Md. at 232. The Court could well conclude that partial legalization

also “change[s] the . . . landscape significantly,” id. at 225, further

reducing an officer’s level of certainty about whether the odor of

cannabis is indicative of criminal activity. After all, the Court has

recognized that reasonable suspicion cannot depend on factors

which are both consistent with innocent behavior and “too

commonplace to be probative in tending to show criminal activity.”

Ferris, 355 Md. at 386-87. “[F]actual circumstances which ‘describe

a very large category of presumably innocent travelers’ cannot, in

and of themselves, justify a seizure.” Id. (quoting Reid v. Georgia,

448 U.S. 438, 441 (1980)). Thus, it may be that the legalization of

some possession and use of cannabis will make the odor of cannabis

so common as to be legally insufficient to support a finding of even

reasonable suspicion. Cf. Moore, 488 P.3d at 819-21 (concluding,

in light of a state law permitting “the possession and transport of

[cannabis], in a variety of amounts and forms,” that even a “very

strong odor” of cannabis is “not a specific enough articulation to

adequately support reasonable suspicion that [cannabis] [is]

therefore present in [a] vehicle in an unlawful quantity”).

On the other hand, the Court in In re D.D. described a stop as

“a relatively minor intrusion” on one’s “freedom of movement”

and emphasized “[t]he public interest in investigating and

prosecuting criminal offenses” and the Court’s desire to avoid

“significantly hamper[ing] the legitimate investigation of criminal

activity in Maryland.” 479 Md. at 233, 238, 241. The Court also

reaffirmed “key language” from Robinson “that the odor of

[cannabis] still provides evidence of a crime,” “even if it may not

Gen. 153] 195

rise to the level of probable cause in every situation.” Id. at 235.

As already noted, the relevant crimes identified in Robinson

(possession of a criminal amount of cannabis and distribution

crimes) will remain crimes under the impending legalization

scheme. But perhaps most significantly, the Court observed that

“it would be peculiar if the odor of [cannabis] was sufficient to

meet the higher standard of probable cause needed to search a

vehicle, but insufficient to meet the lower standard of reasonable

suspicion needed to briefly stop a person on the street.” Id. at 236.

If we are correct that, under the legalization scheme, the odor of

cannabis will still authorize officers to search a vehicle, then it

seems likely that the Court of Appeals would hold that officers still

have the authority to briefly detain someone who smells of cannabis.

As the Court emphasized in In re D.D., however, any detention

will have to “be brief, especially in light of the reality that many

individuals who choose to possess [cannabis] do so under the

criminal threshold.” Id. at 233-34. “[I]f the officer does not quickly

obtain additional information that provides probable cause to believe

that the person has committed a . . . criminal offense, the officer”

will have to “allow the person to go on their way.” Id. at 233.

III

Conclusion

Although by no means clear, it is our opinion that, under the

impending legalization of some use and possession of cannabis, the

Court of Appeals would more likely hold that police officers can

still search a vehicle that smells of the drug. But the odor of

cannabis emanating from a vehicle will not, without more, permit

a police officer to search the vehicle’s occupants. The partial

legalization of cannabis also calls into question the use of drug-

sniffing dogs to establish probable cause for a vehicle search, if

those dogs are trained to detect cannabis. Beyond the vehicle

context, the odor of cannabis coming from a person, without more,

will not authorize a police officer to arrest and search that person,

but the odor will likely allow an officer to briefly stop the person

to investigate whether they have a criminal amount of cannabis.

Brian E. Frosh

Attorney General of Maryland

Rachel A. Simmonsen

Assistant Attorney General

Patrick B. Hughes

Chief Counsel, Opinions and Advice