Lorazepam impairs highway driving performance more than heavy alcohol consumption

Accid Anal Prev. 2013 Nov;60:31-4. doi: 10.1016/j.aap.2013.08.004. Epub 2013 Aug 18.


While research indicates that benzodiazepine (BZD)-like drugs impair driving performance, it remains unclear (i) how far BZDs affect lane-keeping performance, compared with alcohol and (ii) to what extent this impact can realistically be measured in a simulated environment. To clarify these issues, 16 healthy male drivers who had never previously taken BZDs underwent a randomized, crossover, double-blind, placebo-controlled driving paradigm (with the BZD lorazepam) in both real-world and simulated settings. Two lane-keeping variables, namely inappropriate line crossings (ILCs) and standard deviation of lateral position (SDLP), were recorded during the driving sessions. Analyses revealed that (i) a single lorazepam dose (2 mg given by mouth) caused higher SDLP increases than a blood alcohol concentration of above 0.05%, and that (ii) this BZD effect was amplified in the simulated driving setting, mainly for ILCs. As a consequence, we recommend that physicians be made more aware of BZD-related risks and that researchers make a clear distinction between the effects of BZD intake per se and the impact of simulated driving settings.

Keywords: Benzodiazepine; Line-crossing; On-road driving; Simulator; Weaving.

Publication types

  • Comparative Study
  • Randomized Controlled Trial
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adult
  • Alcohol Drinking / adverse effects*
  • Anti-Anxiety Agents / adverse effects*
  • Automobile Driving / psychology*
  • Computer Simulation
  • Cross-Over Studies
  • Dose-Response Relationship, Drug
  • Double-Blind Method
  • Healthy Volunteers
  • Humans
  • Lorazepam / adverse effects*
  • Male
  • Models, Theoretical
  • Psychomotor Performance / drug effects*


  • Anti-Anxiety Agents
  • Lorazepam