Distraction and driving: results from a case-control responsibility study of traffic crash injured drivers interviewed at the emergency room

Background: Use of cellular phones has been shown to be associated with crashes but many external distractions remain to be studied.

Objective: To assess the risk associated with diversion of attention due to unexpected events or secondary tasks at the wheel.

Design: Responsibility case-control study.

Setting: Adult emergency department of the Bordeaux University Hospital (France) from April 2010 to August 2011.

Participants: 955 injured drivers presenting as a result of motor vehicle crash.

Main outcome measures: The main outcome variable was responsibility for the crash. Exposures were external distraction, alcohol use, psychotropic medicine use, and sleep deprivation. Potential confounders were sociodemographic and crash characteristics.

Results: Beyond classical risk factor found to be associated with responsibility, results showed that distracting events inside the vehicle (picking up an object), distraction due to driver activity (smoking) and distracting events occurring outside were associated with an increased probability of being at fault. These distraction-related factors accounted for 8% of injurious road crashes.

Limitations: Retrospective responsibility self-assessment.

Conclusions: Diverted attention may carry more risk than expected. Our results are supporting recent research efforts to detect periods of driving vulnerability related to inattention.