Drug-Impaired Driving in the Age of Legalization 2017 STRATEGIC HIGHWAY SAFETY SUMMIT AND AAA DRUGGED DRIVING SYMPOSIUM Nathan Warren-Kigenyi Manager of Traffic Safety Research & Analysis AAA National Office ● Washington, DC

817% The Washington State Dept of Health / CDC Behavioral Risk Factor Surveillance System has been measuring the prevalence of marijuana use in the state since 2011 (asks about any use and number of days used in past 30). The survey showed a small increase in the percent of the population that reported using marijuana at all.  It increased by somewhere in the ballpark of 2 percentage points from before legalization to after, but the increase in use was not nearly as large as the increase in prevalence among drivers in fatal crashes.  This suggests (strictly speaking, does not actually prove, but in my opinion pretty strongly suggests) that in addition to more people using marijuana generally, the prevalence of driving shortly after using marijuana increased even more in the 1-2 years after legalization.

In 2014, 1 in 6 drivers involved in fatal crashes in Washington State had recently used marijuana

Marijuana Legalization Laws November 2016 (D.C.) States with marijuana per se blood limits Colorado * 5 ng/mL Illinois 5 ng/mL Montana 5 ng/mL Washington 5 ng/mL Nevada 2 ng/mL Ohio 2 ng/mL Pennsylvania 1 ng/mL Legalized for recreational and medicinal use (8 states + D.C.) Legalized for medicinal use only (20 states) Not legal (22 states) *In Colorado, 5 ng/mL = permissible inference a person was under the influence of drugs.

Better Alternative to Per Se Laws What gets you pulled over Results of a SFST Opinion of a Drug Recognition Expert Positive blood test for active THC

Reasons for Misinformation Vocabulary Misuse Dearth of Research Internal Validity of Early Research Federal vs. Street Cannabis & DUI Arrest/Conviction Data Cannabis & Crash Data Peak THC Blood Levels ≠ Peak Impairment

Blood v. Brain THC Levels Distribution of THC in the body. The distribution of THC after a single administration in plasma and body tissues. Note the ‘biphasic’ disappearance in plasma. The rapid phase (in minutes) indicates a rapid uptake of the drug by fat-containing tissues. The slow phase (in days) shows the release of THC by these tissues (Nahas, 1975). THC, tetrahydrocannabinol.

How often does drugged driving cause crashes? Roadside drug tests not widely available - (and no model specifications) LE don't usually test for drugs if driver has BAC ≥ 0.08 because (1) enough evidence for a DUI charge and (2) cost and (3) time. Crash involved drivers and poly-drug use hard to know which substance had the greater effect DATA

Data Barriers Report & Policy Recommendations More & Better Data on drugged driving Policy/Advocacy

Marijuana Legalization AAA’s Position Traffic Safety Implications Medicinal Marijuana Future Research and Considerations

Nathan Warren-Kigenyi Thank You! Nathan Warren-Kigenyi Nwarrenkigenyi@national.aaa.com