Pubdate: Wed, 30 Nov 2011
Source: Wall Street Journal (US)
Copyright: 2011 Dow Jones & Company, Inc.
Contact:  http://www.wsj.com/
Details: http://www.mapinc.org/media/487
Author: Christopher Shea

DO MEDICAL-MARIJUANA LAWS REDUCE HIGHWAY DEATHS?

Medical-marijuana laws reduce traffic deaths, according to a new 
study, probably because people in states with such laws partly 
substitute marijuana for alcohol - and alcohol is more deadly when 
combined with driving.

Fifteen states plus the District of Columbia have passed 
medical-marijuana laws since 1996. Examining National Highway Traffic 
Safety Administration data before and after the passage of those laws, 
the researchers found a nearly 9% decrease in overall traffic 
fatalities. (The calculations also took account of trends in 
neighboring states.) That decline was caused entirely, or nearly so, 
by a drop in alcohol related traffic deaths.

In states that have legalized medical marijuana, the researchers found 
evidence of an increase in marijuana consumption-beyond prescription 
uses - among people over 18 (but not under 18).* According to their 
analysis of data collected by the Centers of Disease Control and the 
states, those states have also seen a slight drop in alcohol 
consumption. Taken as a whole, the data suggest that marijuana is 
being used as a partial replacement for drinking, and not only a 
supplement to drinking.

Like alcohol, marijuana hinders physical coordination. People who are 
high, however, tend to be more aware of their intoxication, and less 
aggressive and reckless, than people who are drunk, the researchers 
said. Another factor in the fatality drop may be that people consume 
marijuana in private, rather than in bars (or sports stadiums) they 
drive home from.

Source: "Medical Marijuana Laws, Traffic Fatalities, and Alcohol 
Consumption," D. Mark Anderson and Daniel I. Rees, Institute for the 
Study of Labor working paper (November)

*That medical-marijuana laws lead to more marijuana use among adults 
was the general trend, but it wasn't universal. Montana, where nearly 
3% of the population has a marijuana prescription (!), and Rhode 
Island, where only some 3,000 people do, both saw increases in pot 
consumption. Vermont, however, with a medical-marijuana patient roster 
measured in the hundreds, did not see an increase in pot consumption.
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