2015-06-03 16:43:36

Whenever there are people debating the merits of legalizing marijuana, you can be fairly certain that someone will state that legalization will make the roads less safe. These people will often argue that if people are legally smoking weed for recreation, or using medical marijuana cigarettes, or medical cannabis vaporizer devices in large groups; that there will be more intoxicated people driving, and therefore more accidents. Is there any truth to this fear? An article in the Washington Post*, by Radley Balko, suggests that there may not be.

Positive Testing Versus Intoxication

Balko begins his argument by discussing the difference between testing positive for marijuana and being intoxicated by marijuana. At this time, there is only one test that can be performed to find out if someone has used marijuana. It simply tells you whether or not someone has used the drug; it cannot indicate if the person has used so much that they are inebriated or impaired by it.

He points this out to argue a claim made by an anti-marijuana group that the number of people driving under the influence in Washington increased by more than 30 percent after legalization, but before the first marijuana store opened. Balko posits that there is no way of knowing if those people actually were a threat while on the road. Plus, a person can test positive for many days after use, so it's possible they hadn't even used a recreational or medicinal marijuana vape pen, or smoked a joint on the same day they were tested.

Raw data from the Colorado Dept. of Transportation

Raw data from the Colorado Dept. of Transportation

Rising Numbers versus Rising Incidences

Another point that Balko effectively argues is that you cannot state that the fact that there have more accidents involving people who tested positive for marijuana, in states where medical cannabis is legal, is proof that pot legalization makes the highways more dangerous. He explains that it's logical that once marijuana is legal, a larger percentage of people will use the drug than before. He states that there would be a larger percentage of people in all groups who used the drug more than prior to legalization simply because it's legal. In doing so, he clarifies the differences between rising numbers versus rising incidences; to truly prove that marijuana legalization makes the roads more dangerous for drivers, someone would need to show that there were more traffic accidents in total after legalization than there were before. To read more about pros and cons of medical marijuana click here.

Colorado: A Case Study

To truly examine how marijuana legalization impacts highway safety, Balko goes on to analyze the conditions in Colorado, which legalized marijuana in 2014. He included a graph that clearly showed the number of fatal traffic accidents from month to month from January through July from 2002 to 2014. In 2014, traffic accidents were lower than 2013 and below the 13-year average.

Next, Balko added together the worst totals each month and the best total from each month and created a bar graph, putting the total number of traffic accidents that occurred in 2014 beside the worst numbers, the best numbers, the average numbers, and the 2013 numbers. The 2014 numbers were the second lowest, closer to the lowest or safest numbers.

Balko then explains that when you look at other states where marijuana was made legal for medical purposes, traffic fatality numbers have fallen even though more drivers have tested positive for pot. He does point out there could be flaws with his hypothesis, stating that cars are of course safer now than they were 10 years ago.

Raw data from the Colorado Dept. of Transportation

Raw data from the Colorado Dept. of Transportation

The Takeaway

While it may not be possible to argue that marijuana usage is actually decreasing the number of fatalities due to auto accidents, it is clear that many of the arguments against marijuana legalization will make the roads more dangerous are not valid or fair. It goes to show that you need to think critically about data, and not blindly accept statistics as facts.


Reference:

  • Washington Post*
  • Colorado Dept. of Transportation
  • Marijuana Driving Cases in Washington State
  • Marijuana, Alcohol and Traffic Fatalities
  • Trends in Alcohol and Other Drugs

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