Drugs & Driving: What now and what next? Road Safety Research Office Ministry of Transportation of Ontario CARSP Conference 2016

What is the situation? 2013 collision data: 64 road users killed by drivers who had used drugs

What is the situation? 2013 collision data: 64 road users killed by drivers who had used drugs 2013 coroner data: 39% of drivers killed tested positive for drugs*

What is the situation? 2013 collision data: 64 road users killed by drivers who had used drugs 2013 coroner data: 39% of drivers killed tested positive for drugs* 2014 roadside survey data: 10.5% of sampled drivers were drug-positive

What do we know? There is existing technology for detecting drug presence at roadside. Oral Fluid Screening Devices

What do we know? There is existing technology for detecting drug presence at roadside. Oral Fluid Screening Devices There is an existing test battery for detecting impairment at roadside. Standardized Field Sobriety Test

What don’t we know? Despite having methods to test for drug presence and drug impairment, presence and impairment is not a one-to-one relationship.

Marijuana has impairing effects. (per lab & simulator studies) Attention Reaction time Distance perception Speed variability Car following Lane positioning

Effect estimates of marijuana on collision risk are mixed (per epidemiology studies). Differences in biological samples

Effect estimates of marijuana on collision risk are mixed (per epidemiology studies). Differences in biological samples Confounding factors, e.g., age, sex

Effect estimates of marijuana on collision risk are mixed (per epidemiology studies). Differences in biological samples Confounding factors, e.g., age, sex Misclassification of exposure

Effect estimates of marijuana on collision risk are mixed (per epidemiology studies). Differences in biological samples Confounding factors, e.g., age, sex Misclassification of exposure Specific populations

What are we doing about this? Calculating an Ontario-specific estimate of collision risk from marijuana. Different places, different usage habits?

What are we doing about this? Calculating an Ontario-specific estimate of collision risk from marijuana. Different places, different usage habits? Mediated by “driver profile”? E.g., collision history, conviction history

HOW are we doing this? Recall from earlier slide: 2013 coroner data: 39% of drivers killed tested positive for drugs* 2014 roadside survey data: 10.5% of sampled drivers were drug-positive

Update 2013 coroner data to 2014 Recall: 2013 coroner data: 39% of drivers killed tested positive for drugs* 2014 roadside survey data: 10.5% of sampled drivers were drug-positive Update 2013 coroner data to 2014

Adjust for confounders, e.g., age, sex Recall: 2013 coroner data: 39% of drivers killed tested positive for drugs* 2014 roadside survey data: 10.5% of sampled drivers were drug-positive Update 2013 coroner data to 2014 Adjust for confounders, e.g., age, sex

Adjust for confounders, e.g., age, sex Recall: 2013 coroner data: 39% of drivers killed tested positive for drugs* 2014 roadside survey data: 10.5% of sampled drivers were drug-positive Update 2013 coroner data to 2014 Adjust for confounders, e.g., age, sex Adjust thresholds to reflect recent usage

Adjust for confounders Adjust thresholds to reflect recent usage Recall: 2013 coroner data: 39% of drivers killed tested positive for drugs* 2014 roadside survey data: 10.5% of sampled drivers were drug-positive Update 2013 coroner data to 2014 Adjust for confounders Adjust thresholds to reflect recent usage Isolate the “marijuana-only” cases

Adjust for confounders Adjust thresholds to reflect recent usage Recall: 2013 coroner data: 39% of drivers killed tested positive for drugs* 2014 roadside survey data: 10.5% of sampled drivers were drug-positive Update 2013 coroner data to 2014 Adjust for confounders Adjust thresholds to reflect recent usage Isolate the “marijuana-only” cases Match for time of day, day of week, etc.

Next Steps Monitor literature for emerging evidence on drugs and driving, particularly cannabis and driving. Continue with our in-house collision risk estimate, with results by year end.

Tracey Ma Team Lead, Special Projects Road Safety Research Office Ministry of Transportation tracey.ma@ontario.ca