# Bernal v. Bernhardt > Supreme Court of Iowa · October 13, 1970 · 180 N.W.2d 437 URL: https://www.frixlaw.com/law-library/cases/9685609 ## Case - **Full name:** Celestino BERNAL, Appellee, v. Roger Eugene BERNHARDT, Appellant - **Court:** Supreme Court of Iowa - **Decided:** October 13, 1970 - **Citations:** 180 N.W.2d 437; 1970 Iowa Sup. LEXIS 915 - **Precedential status:** Published - **Opinion:** Dissent by Larson - **Judges:** Stuart, Moore, Rees, Uhl-Enhopp, Rawlings, Becker, Legrand, Larson, Mason - **Cited by:** 14 later opinions in the Frix Law Library ## Citator (automated) - No negative treatment found by the automated citator. That is not the same as a confirmation that the case is good law; read the citing cases. - Full citator and citing cases: https://www.frixlaw.com/law-library/cases/9685609 ## Opinion text LARSON, Justice. I respectfully dissent. In my opinion the trial court erred in granting a new trial for I feel the testimony of Officer Lind was properly admitted as evidence that could be legally helpful to the jury. I believe that the officer was properly qualified as an expert and that a substantial and sufficient basis for the expression of his opinion does appear. It is unnecessary to show him an expert in all methods of determining speed from skid marks and it need not appear that he considered all of them in order to express his opinion here. *443 The majority seems to assume that the engineering formula set out in Hedges v. Conder, Iowa, 166 N.W.2d 844 , is the only method of determining the speed of the car from observing the skid marks it left on the pavement. While that formula may be correct and is usually accepted by courts of law as a proper means of measuring speed, the majority apparently forgets that we also held in Hedges v. Conder, supra, that occupational training plus years of practical experience have likewise been established as a valid basis upon which an expert opinion may be based. In that case, in addition to mentioning the accepted formula, we also quoted with approval from McCormick on Evidence, § 13, as follows: “To warrant the use of expert testimony, * * * two elements are required. First, the subject of the inference must be so distinctly related to some science, profession, business or occupation as to be beyond the ken of the average layman, and second, the witness must have such skill, knowledge or experience in that field or calling as to make it appear that his opinion or inference will probably aid the trier in his search for truth. The knowledge may in some fields be derived from reading alone, in some from practice alone, or as is more commonly the case, from both.” Officer Lind’s background clearly shows that he qualified under this rule by both study and occupational experience to render an opinion that would be helpful to the jury. The record shows that he has attended several schools of traffic safety, that he has conducted skidding experiments on his own at different accident sites, and that he has investigated accidents of this type during the course of his work at a rate of 10 to 15 times a month for 11½ years. He even made tests at the scene of some accidents using the vehicles involved. With the aid of other officers tests were made with different models of passenger cars and trucks, and measurements were made after brakes were applied at different known speeds. He testified he had observed the topography of the highway in this case and compared it with other known situations involving a slight uphill grade. He further stated he observed the condition of the road surface, that he was familiar with the coefficient of friction and knew this factor was used by some experts to determine speed, but that in this case he did not find it too helpful and did not consider it here. The majority seems to hold, because he did not know the exact weight of the vehicle here or the type of tires it had, and did not think the surface of the tires or the vehicle’s weight made much difference under these circumstances, this disqualified his opinion. I strongly disagree. I do not think under such a showing that we should disqualify his opinion and hold that only opinions based upon academic expertise may be heard by the jury, as the majority appears to indicate. The purpose of expert testimony is to aid the jury by setting before it information not available to the average layman. Dougherty v. Boyken, 261 Iowa 602 , 155 N.W.2d 488 ; Brower v. Quick, 249 Iowa 569 , 88 N.W.2d 120 ; Brandt v. Richter, Iowa, 159 N.W.2d 471 . It should be admitted when it seems reasonably capable of helping the jury, and not excluded merely because the expert failed to recite analytical elements found useful by other experts in the field. It may be that the majority is concerned with the possibility that in this or future cases a jury will be overly-impressed by the testimony of someone such as Officer Lind who is clothed with public authority. To this it is sufficient-to state that expert testimony is subject to the testing and scrutiny of cross-examination, which may or may not affect its credibility. In the case at bar opposing counsel pointed out in cross-examination that other experts in the field relied upon the variables that Officer Lind said were not helpful to him and that he did not use. The jury thus had called to its attention the elements of two acceptable methods of accident analysis and could properly decide what weight to give *444 to the opinion of this officer. This is a proper jury function. Because I believe that Officer Lind’s opinion was of sufficient aid to the jury in determining the speed here, and because I do not feel only academic or technically-qualified persons should be allowed to render opinions on such questions, I would reverse the trial court’s grant of a new trial herein and let the verdict stand. --- Source: Frix Law Library, https://www.frixlaw.com/law-library/cases/9685609. Public record. Not legal advice.