Canadian Journal of Public Health

, Volume 101, Issue 5, pp 353–357 | Cite as

The Additive Effects of Alcohol and Benzodiazepines on Driving

  • Hillary G. Maxwell
  • Sacha Dubois
  • Bruce Weaver
  • Michel Bédard
Quantitative Research



To examine the relationship between the combination of alcohol and benzodiazepines and the risk of committing an unsafe driver action.


We used data from the Fatality Analysis Reporting System (1993-2006) on drivers aged 20 or older who were tested for both alcohol and drugs. Using a case-control design, we compared drivers who had at least one unsafe driver action (UDA; e.g., weaving) recorded in relation to the crash (cases) to drivers who did not (controls).


Drivers who tested positive for intermediate- and long-acting benzodiazepines in combination with alcohol had significantly greater odds of a UDA compared to those under the influence of alcohol alone, up to blood alcohol concentrations (BACs) of 0.08 and 0.05 g/100 ml, respectively. The odds of a UDA with short-acting benzodiazepines combined with alcohol were no different than for alcohol alone.


This study demonstrates that the combination of alcohol and benzodiazepines can have detrimental effects on driving beyond those of alcohol alone. By describing these combined effects in terms of BAC equivalencies, this study also allows for the extrapolation of simple, concrete concepts that communicate risk to the average benzodiazepine user.

Key words

Automobile driving benzodiazepines alcohol drinking drug interactions case control studies 



Examiner la relation entre la combinaison d’alcool et les benzodiazépines et le risque de commettre un action de conducteur dangereux.


Nous avons utilisé les données du Fatality Analysis Reporting System (1993-2006) sur les conducteurs âgés de 20 ans ou plus qui ont été testés pour l’alcool et les drogues. En utilisant un devis cas-témoin, nous avons comparé les conducteurs ayant au moins une action de conduite dangereuse (par exemple, changements de voie fréquent) enregistré par rapport envers les accidents (cas) aux conducteurs qui n’ont pas (contrôles).


Les conducteurs qui ont testés positifs pour les benzodiazépines à durée d’action intermédiaire et à longue durée d’action en combinaison avec l’alcool avaient une probabilité significativement plus élevée de commettre une action de conduite dangereuse par rapport à l’alcool seul, jusqu’à un taux d’alcool de 0,08 et 0,05 g/100mL, respectivement. Les benzodiazépines à effet de courte durée en combinaison avec l’alcool n’étaient pas différents de l’alcool seul.


Cette étude démontre que la combinaison d’alcool et de benzodiazépines peut avoir des effets néfastes sur la conduite au-delà de celles de l’alcool. En décrivant ces effets combinés sur le plan d’un taux d’alcoolémie équivalent, cette étude permet également l’extrapolation de concepts simples qui communiquent les risques aux utilisateurs de benzodiazépines.

Mots clés

conduite automobile benzodiazépines interactions de drogues études cas-témoins 


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Copyright information

© The Canadian Public Health Association 2010

Authors and Affiliations

  • Hillary G. Maxwell
    • 1
  • Sacha Dubois
    • 1
  • Bruce Weaver
    • 2
  • Michel Bédard
    • 1
  1. 1.St. Joseph’s Care GroupResearch DepartmentThunder BayCanada
  2. 2.Lakehead UniversityNorthern Ontario School of Medicine, Thunder BayCanada

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