647.1Accident Reconstruction

Last Updated: 12/01/23

Key Concepts

  • An expert in accident reconstruction can use known factors from a crash, such as skid marks and the final position of the vehicles, to determine causation, vehicle speed, or driver behavior.
  • A lay witness who personally observed a crash may also express an opinion about vehicle speed and may testify to what happened during the crash.
  • Expert testimony in the field of accident reconstruction is generally admissible as long as a proper foundation is laid.


A properly qualified witness may testify as an expert in the field of accident reconstruction and render an opinion as to how and why an accident occurred. To form that opinion, the analyst will consider known factors such as the final resting positions of vehicles, evidence from the accident scene, witness statements, and vehicle damage. The expert then uses that data to determine other relevant issues such as vehicle speeds, collision severity, visibility, driver behavior, and other causal factors. See State v. Brown, 182 N.C. App. 115 (2007) (in a homicide case involving a multi-vehicle crash, state’s accident reconstruction expert was properly allowed to offer his opinion that one of the drivers was trying to get out of the way of oncoming traffic, based on statements made by one of the drivers and the physical evidence); State v. Holland, 150 N.C. App. 457 (2002) (expert in accident investigation and reconstruction was properly allowed to testify about the accident scene, including the extent and location of damage to the vehicles, the presence of scrapes, gouges, and scuff marks in the pavement, and the location of debris, and to give an opinion about the sequence of events).

Practice Pointer

Questions and Answers
For a more detailed explanation of: (i) the scientific principles behind accident reconstruction; (ii) the factors underlying an analysis; and (iii) quick answers to many common objections and arguments, see Crash Reconstruction Basics for Prosecutors,” American Prosecutors Research Institute, Mach 2003.
Prosecutors should also talk to the expert witness before trial and make sure the direct examination adequately cover the witness’s qualifications, the reliability of the analysis, and the basis for the opinion. For more suggestions and guidance on structuring these questions, see the related entry on Expert Testimony – Generic Question Outline

Rule of Evidence 702(i) allows (upon proper foundation) a witness qualified as an expert in accident reconstruction who has either (i) performed a reconstruction or (ii) reviewed the report of an investigator, to give an opinion as to the speed of a vehicle, even if the witness did not personally observe the vehicle moving. See G.S. 8C-1, Rule 702(i); State v. Davis, 197 N.C. App. 738 (2009), rev’d in part on other grounds, 364 N.C. 297 (2010). The statutory codification of this provision overrode the common law rule, which held that “with respect to the speed of a vehicle, the opinion of a[n]...expert witness will not be admitted where he did not observe the accident, but bases his opinion on the physical evidence at the scene.”  Hoffman v. Oakley, 184 N.C. App. 677 (2007); quoting Marshall v. Williams, 153 N.C. App. 128 (1985).

Lay Opinion Testimony About an Accident

Lay opinion about the cause of an accident is typically not permitted. The witness must be an expert to give such an opinion. See State v. Denton, 265 N.C. App. 632 (2019) (error to allow trooper, who was not qualified as an expert, to offer an opinion about who was driving based on his investigation of the accident scene and the position of seats in vehicle); State v. Maready, 205 N.C. App. 1, 17 (2010) (stating that “[a]ccident reconstruction opinion testimony may only be admitted by experts” and finding that it was error to allow officers’ opinion testimony concerning their purported accident reconstruction conclusions when the officers were not qualified as experts); but see State v. Skinner, 242 N.C. App. 522 (2015) (unpublished) (EMS worker not tendered as an expert was properly allowed “to testify that defendant's abdominal pain was an ‘indication that possibly [defendant] hit the steering wheel’ when his vehicle rolled over”).

However, lay opinion testimony about the speed of the vehicle generally is permitted. A person who saw a vehicle in motion may properly provide a lay opinion estimating the speed of the vehicle and may properly testify about the sequence of events he or she witnessed that caused the accident. See Nationwide Mutual Insurance Co. v. Chantos, 298 N.C. 246 (1979) (“[A] person of ordinary intelligence and experience is competent to state his opinion as to the speed of a vehicle when he has had a reasonable opportunity to observe the vehicle and judge its speed.”); Blackwell v. Hatley, 202 N.C. App. 208 (2010) (two lay witnesses properly allowed to testify that they “had been across the street and seen the accident, that Hatley was driving no more than 35 mph, and that Plaintiff pulled out in front of Hatley”).

Admissibility and Reliability of Expert Testimony

Numerous criminal cases in North Carolina have found the principles and methodologies of accident reconstruction to be reliable, and have routinely allowed expert testimony about accident reconstruction from a properly-qualified witness. See, e.g., State v. Brown, 182 N.C. App. 115 (2007); State v. Speight, 166 N.C. App. 106, 116-17 (2005), vacated on other grounds, 548 U.S. 923 (2006); State v. Holland, 150 N.C. App. 457, 461-464 (2002); State v. Purdie, 93 N.C. App. 269, 274-76 (1989).

There are not yet any post-2011 published North Carolina criminal cases directly analyzing the admissibility of accident reconstruction experts under amended Rule 702 and the Daubert standard. However, at least one civil case has allowed accident reconstruction testimony under the new Daubert standard. See Pope v. Bridge Broom, Inc., 240 N.C. App. 365, review denied, 368 N.C. 284 (2015) (applying Daubert, and finding that trial court did not abuse its discretion by admitting expert accident reconstruction testimony).

Additionally, several criminal cases decided after the 2011 amendments demonstrate that this type of expert testimony continues to be admitted at trial, although the admissibility of the expert testimony was not the central issue being argued on appeal. See, e.g., State v. Denton, 265 N.C. App. 632 (2019) (state presented testimony from an accident reconstruction expert, who testified that "his theory which placed defendant as the driver made the 'most sense'” but also acknowledged that "this case was very challenging and he simply did not have sufficient information regarding the many variables involved to come to a conclusive determination"); see also State v. Alexander, 255 N.C. App. 214 (2017) (unpublished) (noting that the “testimony in question was provided by Officer Jonathan Derrick, an accident reconstruction expert”); State v. Moultry, 246 N.C. App. 702 (2016) (“Officer Bruining testified as an expert witness of crash investigation and reconstruction and explained to the jury, without objection, that…”); State v. McGarva, 232 N.C. App. 185 (2014) (unpublished) (“Lieutenant James Gaskill of the Morehead City Police Department, who testified as an expert in accident reconstruction…”).

Portions of this entry were excerpted from the North Carolina Superior Court Judges’ Benchbook, “Criminal Evidence: Expert Testimony,” Aug. 2017, Jessica Smith.