Pierre Van Elslande

Powered two-wheelers within the traffic system

The world of powered two-wheelers has changed dramatically in recent decades, along with a steady increase in the number and diversity of the fleet and uses. This evolution has led to some benefits in terms of mobility, but also some drawbacks in terms of safety. The problems involved are neither simple nor monolithic and there is a lack of knowledge about their different facets and backgrounds that require research work both in terms of risk exposure, accidents factors and impact severity. This special issue of Accident Analysis and Prevention regroups 30 papers devoted to an improvement in this knowledge, exploring the different aspects involved in the safety of powered two-wheelers by complementary methods.

Influence of Cannabis on Fatal Traffic Crashes

The influence of cannabis on traffic crashes is a growing concern. Experimental studies provide ample evidence of cannabis influence on psychomotor and cognitive performances. Epidemiological works describe the excess crash risk that this substance causes. Yet this psychotropic drugs influence in causing crashes is still at the center of many discussions. The present analysis exploits crash data in detail to obtain a more precise understanding of the failures that drivers are subject to when they have consumed cannabis, depending on the level of tetrahydrocannabinol (THC) measured in blood samples. Two groups representative of fatal crashes in France were studied: a cannabis group (n = 174) and a control group (n = 174) involving use of neither cannabis nor alcohol. Results of this analysis notably showed that cannabis consumption significantly increased the rate of generalized failures by the driver, reflecting an alteration of all sensorial, motor, and cognitive functions, specifically for high blood levels of THC (>5 ng/mL). At lower levels of intoxication, cannabis leads to a poor diagnosis of driving difficulties.