One of the arguments prohibitionists use against legalization of marijuana, and in particular, recreational marijuana, is that it will result in a surge in highway fatalities caused by “stoned” drivers. This line of reasoning draws on the number of deaths caused by drunk drivers. The prohibitionists also point out that when Colorado “legalized medical marijuana in 2001, there was a surge in drivers found to have smoked pot”. And there have been studies that showed, in states that have legalized medical marijuana, there was an increase in number of drivers testing positive for marijuana who were involved in fatal car accidents.
The key words are “testing positive for marijuana”. Anyone familiar with marijuana knows that it can remain in the body for days and, more often, weeks after using it. The whole purpose and limit of such tests is to see if a person has used marijuana at some point within the time scope of the test. It was never meant to test whether a person is “high” at the time of the test. Marijuana is quite different from alcohol in the length of time it remains in the body, and require entirely different set of tests to truly measure the effect of marijuana on a person’s abilities, if any, at a particular point in time. And any such tests would have to only account for any incremental impact on highway fatalities as a result of legalizing something that was already widely used prior to legalization.
In the absence of such tests, which are the result of the Federal Prohibition on Marijuana, there really is no way to state with certainty one way or the other the effects of legalized marijuana on traffic deaths.
Washington Post did a study last year by simply looking at the data from Colorado’s traffic fatalities before and after legalization of recreational marijuana (WashingtonPost: “Since marijuana legalization, highway fatalities in Colorado are at near-historic lows“).
As the graph shows, the months where recreational marijuana was legalized (2014: Green line) showed a slight decrease from the previous year (2013: Orange line). Both years were lower than the overall average since 2002 (Average 2002-2014: Red line). This graph is significant in what it doesn’t show; it doesn’t show any discernible relationship between recreational cannabis legalization and highway fatalities. If one were reaching to extract a conclusion, it would be that recreational marijuana legalization actually decreased highway fatalities. Those who support this conclusion argue that where it’s legally available, people are substituting marijuana for alcohol. And there is indisputable evidence that alcohol is one of the main causes of highway fatalities.
The Federal Prohibition on cannabis must come to an end so that there can be serious targeted research on the matter and to develop sensible relevant data driven laws and guidelines on driving while stoned.