Robert L. Fox brought this wrongful death action against Todd Allen Dannen-berg, alleging that his son’s death in a one-car accident was caused by Dannen-berg’s negligent driving. The jury rendered a defendant’s verdict, and Fox now appeals the judgment on the verdict as well the district court’s denial of his motion for a new trial. We hold that the district court committed reversible errors by excluding expert testimony and in instructing the jury. Therefore, we reverse and remand for a new trial.
I. BACKGROUND
Derek Fox, the plaintiff’s deceased son, and Todd Dannenberg were roommates at a junior college in Centerville, Iowa. Late on the night of September 22, 1986, they decided to drive to Kansas State University in Manhattan, Kansas, to see Derek’s girlfriend. This was a trip of approximately 275 miles. They left Centerville in Derek’s car and arrived in Manhattan in the early morning hours of September 23rd. Derek Fox drove the entire way from Centerville to Manhattan. They stayed only a few hours and left the Kansas State campus sometime between 10:00 and 11:00 a.m. to return to Centerville. Derek’s girlfriend testified that Derek was driving the car when the boys left her dormitory. The boys stopped and ate at a fast-food restaurant before leaving Manhattan. Dannen-berg testified that he fell asleep in the passenger seat soon after they left Manhattan and that he has no memory of anything that happened from that time until after the accident.
The accident occurred at approximately 2:00 p.m. near the Vivion Road overpass on 1-35 in Kansas City, Missouri. Witnesses reported that the car simply left the road in a gradual manner, hit many large rocks in the embankment, and eventually struck a *1255 concrete pillar supporting the overpass. During the accident the car spun around several times before hitting the pillar. Witnesses who first arrived at the scene testified that both victims had been thrown from the car. Extensive damage was done to the car. Derek Fox sustained severe head injuries and died in the hospital three days later. Todd Dannenberg also sustained severe injuries, but survived.
Derek’s father brought this suit against Dannenberg under the Missouri wrongful death statute, Mo.Rev.Stat. § 537.080 (1986). He claims that Dannenberg was driving the car at the time of the accident and that his negligence caused it. Dannen-berg denies that he was driving. No witnesses to the accident had knowledge as to who was driving. At trial, Fox sought to introduce the expert opinions of two engineers who would testify that based on the damage to the car, the position the car was in and the path it took during the accident, and the boys’ injuries, it could be determined within a reasonable degree of engineering certainty that Dannenberg was driving the car at the time of the accident. The district court refused to admit Fox’s experts’ testimony, ruling that they were not competent to state an expert opinion on who was driving because neither one had medical training. However, the district court allowed Dannenberg’s expert to testify that it would not be possible to determine who was driving the car based on the available facts in this case.
Two other rulings at trial are important in this appeal. First, the district court refused Fox’s request for a jury instruction on res ipsa loquitur. Second, the district court, over Fox’s objection, instructed the jury that it may find from the fact that Derek was driving when the boys left Manhattan that he was also driving at the time of the accident.
After the jury rendered its verdict for Dannenberg, Fox filed a motion for a new trial raising the following issues: (1) the court’s exclusion of his experts’ testimony as to who was driving the car; (2) the court’s admission of Dannenberg's expert’s testimony that the driver of the car could not be determined; (3) the court’s refusal to instruct on res ipsa loquitur; and (4) the court’s instruction to the jury regarding the inference that Derek was driving because he was driving when the boys left Manhattan.
The district court denied Fox’s motion for a new trial. Fox now appeals, raising the same issues.
II. DISCUSSION
A. Expert Testimony
Fox first argues that the district court abused its discretion by excluding his experts’ testimony that Dannenberg was driving the car at the time of the accident. As an initial matter, we reject Dannen-berg’s argument that Fox failed to preserve this issue for appellate review in that he failed to put the expert witnesses on the stand to elicit the proffered testimony. Putting a proffered witness on the stand is not the only way to adequately make an offer of proof. It is also sufficient for counsel to “state with specificity what he or she anticipates will be the witness’ testi-mony_”
Strong v. Mercantile Trust Co.,
The question of whether expert testimony should be admitted or excluded is a matter governed by federal, rather than state, law.
See Warner v. Transamerica Ins. Co.,
If scientific, technical, or other specialized knowledge will assist the trier of fact to understand the evidence or to determine a fact in issue, a witness qualified as an expert by knowledge, skill, experience, training, or education, may *1256 testify thereto in the form of an opinion or otherwise.
Rule 702 reflects an attempt to liberalize the rules governing the admission of expert testimony.
See
J. Weinstein & M. Berger, Weinstein’s Evidence, U 702[02] at 702-30 (1988). The Advisory Notes to the Rule comment that “[t]he rule is broadly phrased. The fields of knowledge which may be drawn upon are not limited merely to the ‘scientific’ and ‘technical’ but extend to all ‘specialized’ knowledge. Similarly, the expert is viewed, not in a narrow sense, but as a person qualified by ‘knowledge, skill, experience, training or education.’ ” Fed.R.Evid. 702, Advisory Note. In
Larabee v. M M & L Intern. Corp.,
It is important also to note that Rule 702 “does not rank academic training over demonstrated practical experi-ence_”
Circle J Dairy, Inc. v. A.O. Smith Harvestore Products, Inc.,
The threshold question of whether a witness is competent as an expert is solely for the trial judge, and, as the text of Rule 702 suggests, the central issue is whether the expert’s testimony will assist the trier of fact. The weight of the testimony is for the trier of fact.
See Mannino,
Once the trial court has determined that a witness is competent to testify as an expert, challenges to the expert’s skill or knowledge go to the weight to be accorded the expert testimony rather than to its admissibility.
See Davis v. American Jet Leasing, Inc.,
With these guidelines in mind, we turn to the district court’s ruling on the expert evidence offered at trial. Fox sought to introduce the testimony of two engineers who would have testified that Todd Dannenberg was driving the car at the time of the accident. The first expert *1257 was Jay Pfeiffer, who is a licensed engineer with a firm that specializes in transportation and accident investigation and analysis. Pfeiffer holds a bachelor’s degree in engineering with additional course work toward a graduate degree. He claims to have specialized in investigating and analyzing traffic accidents for approximately nine years; he has investigated over 1,000 accidents. The second expert was Dr. Thomas E. Mullinazzi, who is the Associate Dean of the School of Engineering at the University of Kansas. He has a doctorate in civil engineering and specializes in transportation engineering. He is a member of several professional engineering organizations and has published papers in his field. He claims that he has 12 years of experience in the investigation and analysis of traffic accidents. Both experts would have based their opinion that Dan-nenberg was driving the car on the following factors: the physical forces operating on the car at the time of the accident, the location of the two boys immediately following the accident, the pattern of the boys’ injuries, and the damage to the interi- or of the car.
The district court did not allow either engineer to testify. The district court reasoned that because one of the factors that Pfeiffer and Mullinazzi would have considered in reaching their opinions was the victims’ injury patterns, they were not qualified because neither one had training or education in medical science. Fox v. Dannenberg, No. 87-0900, slip op. at 5 (W.D.Mo. June 22, 1989).
We believe that this finding was an abuse of discretion. The engineers’ lack of medical training did not render them wholly incompetent to offer expert opinions as to who was driving the car in this case. The question of who was driving is primarily a question of physical science rather than of medical science, and both engineers have significant experience and training in that area. Of course, as the district court recognized, the issue does to some extent involve the science of medicine because one factor that the engineers would consider in forming their opinions is the boys’ injury patterns. However, it is probably inaccurate to say that Pfeiffer and Mullinazzi completely lack the knowledge of medicine that would be required to form this opinion. In their combined 20-plus years of experience in accident reconstruction they undoubtedly have acquired some knowledge of the medical aspects of traffic injury patterns. And, we have recognized that witnesses can acquire expertise through practical training even though they lack formal education in a particular area.
See Davis v. United States,
But, even acknowledging that the engineers’ medical qualifications are lacking, and they are, we disagree with the district court that that gap renders them incompetent to form an expert opinion as to who was driving the car. Pfeiffer and Mullinaz-zi have considerable experience and training in accident reconstruction which, in our opinion, was “sufficient to cross the threshold of admissibility.”
Loudermill,
Moreover, we reject Dannenberg’s contention that the district court’s exclusion of the expert testimony was harmless. Clearly, Fox has virtually no chance of success in this case if he fails to prove that Dannenberg was driving the car at the time of the accident. And, while expert testimony on that issue may not be absolutely necessary, the district court’s exclusion of it substantially undermined his case. This is especially true in light of the district court’s subsequent admission of Dannenberg’s expert’s opinion that there is no way to determine who was driving the car based on the facts and circumstances of the accident.
*1258 We hold that the district court abused its discretion in ruling that Fox’s experts, Pfeiffer and Mullinazzi, were not competent to offer expert opinions as to which boy was driving the car at the time of the accident. The district court committed reversible error in this regard, and thus we reverse and remand this case for a new trial.
We add a final point on the subject of expert testimony in this case. We consider the district court’s admission of Dannen-berg’s expert’s testimony that it is impossible to conclude who was driving the car to be error only in light of the district court’s contemporaneous ruling excluding Fox’s experts’ testimony as to who was driving. On remand, because the district court must admit Fox’s experts’ testimony pursuant to this opinion, it would not be error for the district court also to admit Dannenberg’s expert’s testimony on who was driving or on the unfeasibility of reaching a conclusion as to who was driving, assuming, of course, that a proper foundation is laid.
B. Jury Instruction
Fox next contends that the district court abused its discretion in submitting Instruction 9 to the jury, which read:
Unless and until outweighed by evidence in the case to the contrary, you may find from the fact that Derek Fox was driving the car at the time Derek Fox and Todd Dannenberg left Manhattan, Kansas, that Derek Fox was driving the car at the time of the accident.
Fox, No. 87-0900, slip op. at 7.
The district court has broad discretion in submitting instructions to the jury, and “this court reviews jury instructions to determine whether, taken as a whole, they are confusing or misleading in presenting the principles of law applicable to the case.”
Grogan v. Garner,
Dannenberg submits that Instruction 9 is supported by the Missouri Supreme Court’s decision in
Martin v. Sloan,
We do not agree, however, that the holding in Martin supports the submission of Instruction No. 9 in this case. The facts involved in the instant case — evidence that Fox was driving the car some four hours prior to the accident over 100 miles away from the accident site — are a far cry from the 2.6 miles and few minutes involved in Martin. The court in Martin emphasized that the principle it relied on was very dependent upon the circumstances to which it was applied, and that as the time and distance between the twp events increased, the strength of the inference diminished. Id. The court placed great importance on the fact that the time and distance between when Sloan was seen driving the car and when the accident happened were very short. Id.
*1259 The facts in this case differ substantially. Not only are the time and distance involved in this case far greater than in Martin, in this case there was also some other evidence suggesting that a change in drivers might have taken place. 1 The court in Martin, in concluding that the inference that Sloan was driving was permissible, considered it significant that there were no other circumstances that detracted from the conclusion that Sloan was driving. Id. Applying the same reasoning, it is significant in this case that there was some evidence that the boys changed drivers. That evidence made the court’s instruction on the inference that Derek Fox was driving even more inappropriate.
Accordingly, we believe that the district court abused its discretion in instructing the jury that it could infer from the fact that Derek was driving when the boys left Manhattan that he was also driving when the accident happened. The principle announced in
Martin
does not support the instruction in this case. That principle depends to a great extent on the particular circumstances in a given case, and is appropriate only where the events at issue have a quality of permanence to them that makes the inference reasonable.
See id.
at 256-57;
State v. Donahue,
C. Res Ipsa Loquitur
We next address Fox’s argument that the district court erred in refusing to instruct the jury on the doctrine of res ipsa loquitur. Under Missouri law, res ipsa loquitur is a rule of evidence which “permits a jury to infer negligence without proof of specific negligence.”
Marshall Interiors, Inc. v. Young Men’s Christian Ass’n. of Greater St. Louis, 787
S.W.2d 329, 331 (Mo.App.1990). Res ipsa loquitur only applies when “(a) the occurrence resulting in injury was such as does not ordinarily happen if those in charge use due care; (b) the instrumentalities involved were under the management and control of the defendant; (c) and the defendant possesses superior knowledge or means of information as to the cause of the occurrence.”
Willis v. Terminal Railroad Ass’n. of St. Louis,
Fox argues that under Missouri law res ipsa loquitur applies in one-car accident cases, and cites us to
Fellows v. Farmer,
Further, our research indicates that more recent Missouri cases have also applied res ipsa loquitur in one-car accident cases.
See Fields v. Berry,
Of course, before a res ipsa loquitur instruction is warranted in this case, Fox must fulfill the second requirement of the doctrine by showing that at the time of the accident the car was under Dannenberg’s control. We want to emphasize that our holding that the facts of this case permit the inference of negligence does not relieve Fox of the burden of proving that Dannen-berg was driving the car at the time of the accident. Rather, if the identity of the driver is proven by a preponderance of the evidence, res ipsa loquitur provides an inference that the accident was caused by his negligence.
Finally, it is clear that the third requirement of res ipsa loquitur is met in that Dannenberg’s knowledge of the cause of this accident, although possibly minimal under the circumstances, is certainly superior to Fox’s knowledge.
Accordingly, we hold that on remand the jury should be instructed that if it finds that Dannenberg was driving the car at the time of the accident, it may, pursuant to the doctrine of res ipsa loquitur, infer that the accident was caused by his negligence. If on remand the district court determines that Fox’s evidence that Dannenberg was driving is insufficient as a matter of law, then, of course, an instruction on res ipsa loquitur would not be warranted. For that matter, if the district court finds Fox’s evidence on that point to be legally insufficient, the case would not be submissible to the jury under any set of instructions.
III. CONCLUSION
In sum, we hold that the district court abused its discretion: (1) by excluding the expert testimony of Fox’s experts on the issue of the identity of the driver; (2) by instructing the jury that it may infer from *1261 the fact that Derek Fox was driving when the boys left Manhattan that he was also driving when the accident happened; and (3) assuming that the evidence that Dan-nenberg was driving was not insufficient as a matter of law, by failing to give an instruction on the doctrine of res ipsa loqui-tur. Consequently, we reverse and remand this case to the district court for further proceedings consistent with this opinion.
Notes
. Fox introduced evidence that Todd Dannen-berg was wearing different clothes at the accident scene from what he was wearing when the boys left the dormitory in Manhattan, indicating that the boys stopped at some point and suggesting that the stop provided an opportunity to switch drivers. There was also evidence, and in fact it appears to be undisputed, that the boys stopped to eat before leaving Manhattan. And, Fox suggests that the fact that Derek Fox did all the driving and got no sleep on the trip to Manhattan is some evidence that Dannenberg, who had slept, helped drive on the return trip the next day. Finally, there was testimony that on a previous trip several weeks before the accident Dannenberg had driven Derek Fox’s car on the return trip.
We make no comment on the persuasiveness of this evidence. We mean only to point out that there was some evidence that was contrary to the conclusion that Derek Fox did all the driving.
. We also note that the language used in framing the inference was not altogether accurate. The only undisputed fact relative to the inference was that Derek was driving when the boys pulled away from the dormitory where they visited Derek’s girlfriend. Derek’s girlfriend so testified. Transcript, Vol. I at 152, and Fox appears to agree. Appellant’s Brief at 2. In Instruction No. 9, however, the district court treated as undisputed the fact that "Derek Fox was driving the car at the time [the boys] left Manhattan." Fox, slip op. at 7 (emphasis added). It does not appear that that fact was undisputed, as the district court’s instruction implied. Fox appears to admit only that Derek was driving when the boys left his girlfriend’s dormitory. It seems to us an important point in light of the fact that Fox's theory in this case is that the boys changed drivers after they left the Kansas State campus, and he seems to suggest that the change may have occurred when the boys stopped to eat before leaving Manhattan.
