Banner for The Criminal Justice Systems: A Guide for Law Enforcement Officers and Expert Witnesses in Impaired Driving Cases

Toxicologists, Crash Reconstructionists,
Optometrists, and Other Medical Personnel


Some impaired-driving cases may include additional witnesses from the medical profession: emergency medical technicians (EMTs), nurses, doctors, or even medical examiners (MEs) and forensic pathologists. As with other expert witnesses, if called to testify, medical personnel will be asked to describe their professional training and experience before discussing the specifics of their role in this case.

EMTs, nurses, and doctors can all expect to describe their observations of the defendant and/or victim(s) at or near the time of the incident:


  • What were his responses to your questions and directives—were they coherent and appropriate?
  • What did he say and  how did he say it (slurred, slow, rapid, difficult to understand due to speech pattern or rambling word choice)?
  • Was there any indication of alcohol and/or drug ingestion? Provide details.
  • Was there any indication of head trauma—pupil reaction, etc.?
  • What was the defendant’s physical appearance—injuries, lack of injuries, bleeding, vomiting, urinating on himself, neat or disheveled appearance, clothing appropriate/inappropriate for weather conditions?
  • Was the defendant combative or cooperative?
  • If there were injuries, please describe the degree and probable cause (e.g., head lacerations – due to striking the windshield – which required numerous stitches).

Injured Victim:

  • What were his responses to your questions and directives—were they coherent and appropriate?
  • If not, any indication of head trauma?
  • What was the degree and probable cause of injuries (e.g., broken ribs due to impact with steering wheel)?
  • What was the nature and extent of medical treatment, including prognosis?

The crime of vehicular assault may require a showing of the seriousness of the injuries sustained by the victim. In some States, the seriousness of the injury will directly correlate to the seriousness of the charge against the defendant—a more seriously injured victim will result in a more serious charge against the defendant resulting in the possibility of a lengthier prison sentence if convicted.

It is important to meet with the prosecutor prior to testifying to discuss your knowledge and observations and to answer any questions you might have. You may have questions regarding the impact of HIPAA (Health Insurance and Portability and Accountability Act) which you can discuss with both your employer and the prosecutor.