Proposition 19: Will Legalized Marijuana Lead to Unsafe Streets?

One of the more celebrated ballot propositions appearing on next month’s ballot is Proposition 19 a measure that would legalize possession and smoking of Marijuana for people over the age of 21 under state law. Meanwhile, the Federal Government has vowed to continue enforcing a federal prohibition on marijuana regardless of the vote of California voters.

For many law enforcement agencies, the passage of Prop. 19 is a scary idea.  Not only would they be receiving different instructions from the Federal and State governments.  Agencies are also concerned that passage will lead to an army of stoned drivers taking to the street and imperiling themselves, other drivers, and other road users.

Recently, Los Angeles City Attorney Carmen Trutanich has launched a strange public relations campaign to try and “discover” the impact of smoking marijuana on driving.  What makes it strange?  Instead of using a scientific method and having a control group; Trutanich and the California Highway Patrol are basically giving marijuana to media personalities, letting them smoke it and putting them behind the wheel.  If I didn’t know any better, I might think this was a publicity stunt.

Amongst the media personalities that have taken Trutanich’s bait is L.A. Times columnist Steve Lopez who wrote a recent column on his adventures with controlled marijuana use.  Under the supervision of a couple of amused CHP officers, Lopez smoked a joint of something called “Train Wreck” before being taken to a testing course and put behind the wheel of a Crown Vic.  Lopez reports that neither himself or ABC Radio personality Peter Tilden passed the test with flying colors.

With all do respects to the testing of Professor Trutanich, actual studies on the impacts of marijuana use on drivers is somewhat harder to determine.  The National Highway Traffic Safety Administration, a branch of the Federal Government, has done its own testing with a somewhat more rigorous scientific testing model.  They discovered that:

Marijuana has been shown to impair performance on driving simulator tasks and on open and closed driving courses for up to approximately 3 hours. Decreased car handling performance, increased reaction times, impaired time and distance estimation, inability to maintain headway, lateral travel, subjective sleepiness, motor incoordination, and impaired sustained vigilance have all been reported. Some drivers may actually be able to improve performance for brief periods by overcompensating for self-perceived impairment. The greater the demands placed on the driver, however, the more critical the likely impairment. Marijuana may particularly impair monotonous and prolonged driving. Decision times to evaluate situations and determine appropriate responses increase. Mixing alcohol and marijuana may dramatically produce effects greater than either drug on its own.

Meanwhile, tests that are done out of the United States seem to come up with a different result.  In the Netherlands, Professor HWJ Robbe of the Institute for Human Psychopharmacology, University of Maastricht, completed his own test on the impacts of rolling a joint and driving a car.  Under three different circumstances he concluded that marijuana has a minimal impact on drivers’ abilities to process information and react if taken in moderation.  Of course, mixing marijuana with another substance while driving can be a deadly combination.  Fortunately, imbibing most of those substances is illegal in and of itself.

Unfortunately, science is not pointing us in a clear direction, so educated voters will have to read different studies and make up their mind on which they trust more. You can scour the Internet and find similar results.  Too often the impact of studies on these impacts tend to follow how the local culture views smoking marijuana.  Do you work for the police?  Then the passage of Proposition 19 is intimidating.  Are you one of the sixty percent of Americans who have smoked marijuana?  Then you might gravitate toward studies that point you in another direction.  If you’re stuck in the middle, you have a lot of homework to do between now and election day.