The ActuSAM study conducted by the "Institut Français des Sciences et Technologies des Transports, de l'Aménagement et des Réseaux" (IFSTTAR) updates the SAM (Stupefiants et Accidents Mortels) study conducted in 2005 under the coordination of the OFDT with Bernard Laumon (Ifsttar now) as scientific leader. Based on the analysis of fatal accidents in 2011 recorded in the "Véhicule Occupant Infrastructure Etudes de la Sécurité des Usagers de la Route" (VOIESUR) database, ActuSAM made it possible to quantify and assess the risks associated with the consumption of alcohol or cannabis while driving.
Cannabis is associated with about 4% of fatal accidents, alcohol 28%.
Cannabis is the illigal drug most often detected during screening among the four families tested. The proportion of fatal accidents that would be avoided if no driver were positive for cannabis is estimated at 4.2%. A driver who tests positive for cannabis increases his risk of being responsible for a fatal accident by a factor of 1.65. The results between the SAM study and its update are stable despite the change in the drug control procedure from urinary to salivary screening.
Risque attribuable=Attributable risk = Proportion of fatal accidents that would be avoided in the total absence of exposure (e. g. drivers under the influence of cannabis)
IC : confidence interval. THC : tétrahydrocannabinol (main active molecule of cannabis). OPI : opiates.
Relative reliability on opiates due to a small sample of the population studied
Opiates are substances derived from opium whose effects act on opiate receptors (neurotransmitter receptors). A driver who tests positive for opiates (opium and other derivatives) increases the risk of being responsible for a fatal accident by a factor of 2.21. However, this estimate remains to be confirmed as it is based on a small number of staff. The other drug families are much less consumed, and the associated risks cannot be estimated over a single year of collection.
Drinking and driving, the second leading cause of fatal accidents
The proportion of fatal accidents that would be avoided if no driver were above the 0.5g/l blood alcohol threshold is 28%. The ActuSAM study reassesses the risk of being responsible for a fatal accident among alcoholic drivers. In the SAM study, this risk was 8.5 on average for alcohol-impaired drivers. With the ActuSAM study, this risk is on average 17.8 with a marked dose effect ranging from 6.4 for a dose between 0.5 and 0.8 g/l, 8.3 between 0.8 and 1.2 g/l, 24.4 between 1.2 and 2 g/l and up to 44.4 above 2 g/l.
Risk of being responsible for a fatal or injury accident
OR : odd ratio (likelihood to be responsible). IC : confidence interval.
In addition, ActuSAM insists on the dangerousness of the joint consumption of alcohol and drugs. Among drivers responsible for fatal accidents under the influence of cannabis, more than one in two is under the influence of alcohol. A driver who is positive for both substances increases his risk of being responsible for a fatal accident by a factor of 29.