Pubdate: Tue, 02 Sep 2014
Source: Boston Globe (MA)
Copyright: 2014 Associated Press
Contact: http://services.bostonglobe.com/news/opeds/letter.aspx?id=6340
Website: http://bostonglobe.com/
Details: http://www.mapinc.org/media/52
Author: Joan Lowy, Associated Press

SOME FEAR RISE IN TRAFFIC DEATHS AS STATES LEGALIZE MARIJUANA

WASHINGTON (AP) - As states liberalize their marijuana laws, public 
officials and safety advocates worry that more drivers high on 
marijuana will lead to a big increase in traffic deaths. Researchers, 
though, are divided on the question.

Studies of marijuana's effects show that the drug can slow 
decision-making, decrease peripheral vision, and impede multitasking, 
all of which are critical driving skills.

But unlike with alcohol, drivers high on marijuana tend to be aware 
that they are impaired and try to compensate by driving slowly, 
avoiding risky actions such as passing other cars, and allowing extra 
room between vehicles.

On the other hand, combining marijuana with alcohol appears to 
eliminate the marijuana smoker's exaggerated caution and seems to 
increase driving impairment beyond the effects of either substance alone.

"We see the legalization of marijuana in Colorado and Washington as a 
wake-up call for all of us in highway safety," said Jonathan Adkins, 
executive director of Governors Highway Safety Association, which 
represents state highway safety offices.

"We don't know enough about the scope of marijuana-impaired driving 
to call it a big or small problem. But anytime a driver has their 
ability impaired, it is a problem," he said.

Colorado and Washington are the only states that allow retail sales 
of marijuana for recreational use. Efforts to legalize recreational 
marijuana are underway in Alaska, Massachusetts, New York, Oregon, 
and the District of Columbia. Massachusetts, 22 other states, and the 
nation's capital permit marijuana use for medical purposes.

It is illegal in all states to drive while impaired by marijuana.

Colorado, Washington, and Montana have set an intoxication threshold 
of 5 parts per billion of THC, the psychoactive ingredient in 
marijuana, in the blood. A few other states have set intoxication 
thresholds, but most have not set a specific level. In Washington, 
there was a jump of nearly 25 percent in drivers testing positive for 
marijuana in 2013 - the first full year after legalization - but no 
corresponding increase in car accidents or fatalities.

A roadside survey by the National Highway Traffic Safety 
Administration in 2007 found 8.6 percent of drivers tested positive 
for THC, but it's not possible to say how many were high at the time.

A marijuana high generally peaks within a half hour and dissipates 
within three hours, but THC can linger for days in the bodies of 
habitual smokers.
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