Marijuana and Driving

3/6/3015 - Asm. Adrin Nazarian (D-No. Hollywood/Sherman Oaks) has introduced a bill (AB 24) which would require Uber drivers to submit to random drug testing. It also bans drivers with prior felonies for drug or other offenses in the past 7 years. The bill would subject drivers to a mandatory drug testing program under PUC Code Section 1032.1, which applies to workers under federal interstate transportation regulations.

Cal NORML strongly objects to random drug tests for drivers as an unwarranted violation of personal privacy on the grounds that they have no relation to driver safety. Drug urine tests are unusually sensitive to marijuana, traces of which can be detected weeks after last use, long after any effects have faded. Repeated scientific studies, including a recent new report by the U.S. DOT - NHTSA, have failed to find a reliable connection between the presence of marijuana and driving impairment. Not a single FDA study has ever shown that drug testing is effective in improving highway safety.

The effect of AB 24 will be to unfairly disallow Uber drivers from using marijuana for medicine, even while allowing abuse of many other, more dangerous drugs that aren't tested for, such as synthetic marijuana, sleeping pills, tranquilizers, etc. The only beneficiaries of the bill will be the parasites of the drug testing industry, who have made millions in profits from forcing their unproven, ineffective technology on American workers.

February 26, 2015 - An important new study shows high blood levels of THC can persist days after smoking following heavy use. Levels above 5 ng/ml, the DUI threshold in WA state, were detected as long as 4 days after use. This ought to put the nail in the coffin of proposals to establish mandatory per se THC blood thresholds for DUI. Highway safety researchers would do well to retarget their efforts towards developing better impairment tests, rather than pursue chemical testing for DUI.

December 19, 2014 - For the third consecutive year, Cal NORML was able to derail an ill-conceived “zero-tolerance” DUI bill that would have criminalized all drivers with detectable traces of THC in their system—a population that includes most daily users. NORML experts provided key expert testimony against the bill, and our e-list subscribers sent over 2,100 messages of opposition to legislators.

Numerous accident studies have confirmed that marijuana is not a major risk factor in driving fatalities. In general, however, studies agree that the combination of alcohol and THC is particularly dangerous, if anything worse than "straight" drunken driving.

Read more: "Drug Test Results and Accident Risks" from Cal NORML Guide to Interpreting Drug Test Results

  • U.S.: No evidence marijuana leads to higher crash risk February 2015

    A 20-month survey of drivers in 2013 and 2014 found that drinking and driving dramatically raises the chance of a crash, but didn't find evidence that marijuana use is statistically significant in raising crash rates. See the NHTSA study online


  • Marijuana Arrests Steady, DUIs Decline in CA December 12, 2014

  • Federal Report: Problems with Weed DUI December 08, 2014

  • NHTSA Official Affirms Little Is Known About Stoned Driving August 4, 2014

  • Stoned Drivers: The Case Against Panic; Pot prohibitionists undermine their own warnings about legalization and car crashes. Reason August 11, 2014

  • Accident Stats Show No Evidence of DUI Crisis in California April 29, 2014

  • More Pot, Safer Roads: Marijuana Legalization Could Bring Unexpected Benefits Forbes, April 3, 2014

  • The Myth of California's Drugged Driving Epidemic East Bay Express January 13, 2014

  • Alcohol's role in traffic deaths vastly underreported, study shows Fox News, March 24, 2014




  • Should Per Se Limits Be Imposed For Cannabis? Humboldt Journal of Social Relations, 2013

  • THC Concentrations Don’t Predict Driving Impairment High Times, Oct. 2013

  • VIDEO: Drivers stoned on marijuana test their driving skills (February 2013)

  • Cannabis and psychomotor performance: A rational review of the evidence and implications for public policy Drug Testing & Analysis (September 2012)

  • Cal NORML Successfully Opposes Zero-Tolerance DUI Bill in 2012

  • California posted an impressive 11% decline in fatal auto accidents in 2010. This continues a strong downward trend that started in 2006. Fatalities are down 35% since then. The entire West Coast has experienced similar declines. Colorado also did well, posting a 6.5% in fatal accidents in 2010. As in California, this represents the lowest number of accidents since statistics began in 1994.

  • Driving, Worker Safety Not Affected by Legalization
    July 27, 2010 - A a careful review of the scientific evidence shows that fears about marijuana’s impact on road safety are unwarranted. There is no good scientific evidence that drug testing improves workplace safety.

  • New Studies Confirm: Marijuana a Lesser Driving Hazard than Alcohol - Drug urine tests unjustified.

  • Study Shows Marijuana Users are Safer Drivers

  • Review of accident studies shows marijuana not a major public highway safety hazard, refuting need for "zero-tolerance" DUI laws and bans on public use. Nonetheless, study shows marijuana use is linked to increased injury risk, confirming California NORML's advice to users.

  • Expert review of drug tests and per se "driving under the influence" limits.