When Police Accident Reports are Wrong

Police traffic accident reports provide a good starting point for vehicle crash analysis, but they should never be considered a good end point. Lawyers who represent people injured in vehicle crashes must look past conclusions drawn by investigating police officers  before advising clients about how and when to proceed with a personal injury car accident case.

The most common form of police traffic accident report in Maine is the two or three page computerized form available from the “Maine Crash Reporting” page of Maine.gov. These reports are completed by an investigating officer from notes made in haste, often under difficult, dangerous conditions, at the scene of a collision. In most cases, the officer is not aware of the identity of all of the available witnesses. The officer may even have filed the report without having spoken to each of the drivers involved. Whether favorable or unfavorable to your client, these reports contain only the most rough summary of the crash events and are completely unreliable for use in evaluating the strength or weakness of liability arguments in an injury case.

There is another form of police crash report referred to as an accident reconstruction report. In Maine, the reconstruction report is done only in crashes involving death or catastrophic injury. These reports involve extensive photographic evidence and forensic mapping done by a trained police team using computers and high tech measuring tools. They are generally not available to the public, or even those involved in the crash, for many months after the collision occurs. The delay usually has nothing to do with supplemental investigation or substantive work, only the administrative requirement that the reports be “reviewed” by a supervisor. Even though these reconstruction reports are prepared by trained officers using expensive electronic equipment, there are many reasons why they may be unreliable. The expert witness disclosure below identifies and explains police errors in a particular case (all names have been changed), and then uses the police data to support a conclusion directly contrary to that of the police.

“Plaintiff expects her Expert to testify as follows about the 12/30/2011 crash involving a 2010 Toyota operated by Decedent and a 1997 Dodge van operated by Defendant:

  1. The Accident Reconstruction analysis by the Maine State Police includes erroneous results and conclusions about the actual and relative speeds of the two vehicles.
  2. The documented road conditions and tire marks establish that, contrary to the testimony and statements of Defendant and police conclusions, the Toyota did not travel significantly over the centerline of the roadway.
  3. Proper analysis of the reliable data shows that, prior to the crash, the Dodge van was traveling at an excessive speed.  This speed was a substantial contributing factor in causing the crash.

To the extent that the Expert reviews and relies upon additional information that changes his opinions, this designation will be revised.

    Summary of data supporting each subject matter:

  1. The State Police Accident Reconstruction Conclusions are Unreliable.
    1. The Police used a device known as a Total Station to collect measurement data identifying the location of (a) the post-collision “at rest” locations for the Dodge and the Toyota; (b) tire marks on the roadway; (c) ice in the eastbound lane.
    2. The Police used the collected data to create a Computer Aided Drawing of the accident scene, and then utilized the Drawing to develop pre-and post-impact trajectories for the Dodge and the Toyota.
    3. The Police then used their developed trajectories to reconstruct the accident utilizing traditional accident reconstruction methods.
    4. Comparison of the Total Station data collected by the Police, the scene photographs, and the Drawing demonstrates that the position and scale of the Dodge as shown at rest in the Drawing is incorrect. As a result of this error, the post-impact trajectory of the van as developed and used by the Police is incorrect.
    5. The Drawing and police reconstruction assume that the Toyota traveled in a curved path from the point of impact to its point of rest.
    6. The Total Station data collected by the Police does not include any data points that support this assumption.
    7. Accident scene photographs 13 & 14 show that the Toyota traveled in a straight line from the point of impact to its point of rest.
    8. The post-impact trajectory of the Toyota, as developed and used in the Police reconstruction, is incorrect.
    9. Errors made in calculating the post-impact trajectory of both vehicles caused the momentum calculations used by the Police to assign a greater portion of the combined vehicle momentum to the Toyota than was appropriate, and to over-estimate the pre-crash speed of the Toyota.
    10. In their Reconstruction analysis, the Police also used a “speed loss from rotation” calculation to estimate the amount of speed lost by the Dodge as it deposited tire marks on the roadway prior to impact. In this analysis, the Police reduced the available roadway friction by a factor of 10 during the first 23.7 feet of tire marks and by a factor of 4 for the remaining 38.6 feet.
    11. The accident scene photographs depict pre-impact tire marks from the Dodge which are dark with longitudinal tread ribs clearly visible. This means that the van was not only rotating, but that the Defendant was braking and steering in the direction of the skid during the skid.
    12. Since the Dodge brakes were applied during the skid, the reduction of the coefficient of friction in the police Reconstruction was inappropriate. This means that the Police Accident Reconstruction underestimated the speed lost by the Dodge during the pre-impact phase of the accident.
    13. The combination of errors described makes the police reconstruction inaccurate and unreliable.
  1. The documented roadway conditions and tire marks establish that the Toyota did not travel significantly over the roadway centerline.
    1. The Police identified tire marks on the roadway surface that they attributed to the Toyota.
    2. Marks left on the road by the left front tire of the Toyota are, at their greatest excursion, approximately 7.5 inches over the centerline. The first section of the tire mark is approximately 4° out of parallel with the centerline and curving to the right, indicating that Decedent had steered away from the centerline.
    3. Photographs of the accident scene depict ice, snow, and water in the eastbound lane. The Police established the location of the ice and snow west of the point of impact, but did not establish the location of snow, water, and ice east of the impact.
    4. Comparison of the accident location with the accident scene photographs discloses that the ice, snow, and water east of the point of impact, and at a location 38 feet east of the first documented Toyota tire mark, covered the entire eastbound lane.
    5. If the Toyota had traveled more than 2 feet into the eastbound lane as alleged by Defendant, its left tires would have passed through the wet portions of the roadway.
    6. Wet tire marks from other vehicles which passed through the snowy/wet areas are visible in the scene photographs, but no wet tire marks from the Toyota are visible, indicating that it did not travel across the wet portions of the roadway.
    7. The lack of wet tire marks from the Toyota and the curve of the dry tire marks documented by the Police demonstrate that the Toyota did not significantly cross the centerline of the roadway into the path of the Dodge van.
  1. The Plaintiff’s Accident Reconstruction proves that the Dodge van was traveling at an excessive speed prior to impact, and that this speed was a substantial contributing factor to the accident.
    1. The accident occurred at approximately 12:04 PM on 12/30/11 on Ballard Road in Portland, Maine.
    2. Defendant was operating his van eastbound and Decedent was operating his Toyota westbound.
    3. Ballard Road was divided into single eastbound and westbound lanes by a double yellow line.
    4. The road makes a gentle northerly curve through the area.
    5. The front ends of the two vehicles collided near the northern edge of the westbound lane.
    6. Utilizing the data collected by the Maine State Police, photographs of the accident, measurements of the accident location, and standard motor vehicle data weight and crush data, Plaintiff’s Expert has used standard accident reconstruction techniques to conduct his own reconstruction of the accident.
    7. All angular data mentioned here is provided in degrees measured counterclockwise from the heading of the Dodge van at the point of impact.
    8. The Toyota approached the point of impact at an angle of 156.5° and departed at an angle of 36.7°.
    9. From the point of impact, the Toyota traveled 8.1 feet at a coefficient of friction of 0.7 and 18 feet at a coefficient of friction of 0.55, so its departure speed was approximately 21.6 mph.
    10. The Dodge van traveled a distance of approximately 15.9 feet at an angle of 2° at a coefficient of friction of 0.7 to the point where it overturned, so its departure speed was approximately 18.3 mph.
    11. Using these angles and speeds, a momentum analysis indicates that the Dodge van was traveling at 47.0 mph at the point of impact and the Toyota was traveling at 35.4 mph at the point of impact.
    12. Prior to impact, the Dodge van had deposited tire marks over a distance of 23.7 feet at a coefficient of friction of 0.42 and 38.6 feet at a coefficient of friction of 0.7. Combining these numbers with the 47.0 mph impact speed, it can be calculated that prior to leaving identifiable tire marks, the Dodge van had been traveling at a speed of 57.6 mph. A time period of 0.82 seconds would have passed from the point where the Dodge van began to deposit tire marks to the point of impact.
    13. Prior to impact, the Toyota left 29.3 feet of braking marks identified by the Police. Combining this distance with a coefficient of friction of 0.7 and the impact speed of 35.4 mph, it can be calculated that prior to leaving the identified tire marks, the Toyota had been traveling at a speed of 43.2 mph. A time period of 0.51 seconds would have passed from the point where the Toyota began to deposit tire marks to the point of impact.
    14. The speed limit in the area was 40 mph.
    15. The eastbound travel lane was substantially covered in ice and snow, while the westbound lane was clear.
    16. The tires on the Dodge van were not winter tires.
    17. Defendant was operating his vehicle at approximately 57 mph on a slippery surface, the location at which he claims to have observed the Toyota intrude upon his travel lane, and responded by applying his brakes and steering into the oncoming travel lane.
    18. Prior to impact, Defendant lost control of his van, which rotated clockwise while traveling to the point of impact with the Toyota.
    19. Evidence on the roadway indicates that the Toyota could not have intruded more than 2 feet into the eastbound travel lane. If it were under control, the Dodge van could have continued on in the eastbound lane.
    20. The Dodge van began to deposit identifiable tire marks approximately 0.82 seconds and 62 feet prior to the point of impact.
    21. Adding a 1 second reaction time at the Dodge van travel speed of 57 mph, the defendant driver of the Dodge van would have had to be approximately 146 feet from the point of impact when he saw what he claims to have seen.
    22. Had Defendant been traveling at the posted speed limit of 40 mph with the same available distance and roadway surfaces, he would have been able to slow his vehicle to less than 14 mph at the point of impact and he may have been able to avoid the collision all together.
    23. It is further noted that the Toyota had been traveling on a clear road surface at a speed of approximately 43 mph and was fitted with studded snow tires. There is no physical reason to explain why the Toyota would have entered the eastbound travel lane as Defendant claims it did.

The Expert’s opinions are based upon his review of technical materials; applicable engineering standards; the police reports and related materials; his inspection of the accident site, his inspection of the involved vehicles, and the deposition transcript of Defendant.

Careful study of the scene of the crash and the police photographs, proper inspection of the Dodge and the Toyota, and scrutiny of the police analysis of the collected data turned this case around. The police conclusion that the deceased Toyota driver caused the collision was proven to be incorrect, even though there were no surviving witnesses to the crash other than the defendant van driver. Such is the power of Rule 702 opinion evidence properly developed.

If you or your client are faced with a police traffic accident report that does not make sense, or does not seem right, thinking about the expert opinion standards set forth in Rule 702 might lead you to a more accurate and more satisfying conclusion.

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