Traffic fatalities on a high after cannabis legalisation

Credit: CC0 Public Domain

Monash University research examined the effect of recreational cannabis sales (RCS) on traffic fatalities in three US states where it was legalised—Colorado (legalised 2014), Washington (2014), and Oregon (2015), and nine neighbouring jurisdictions from 2009-2016.

The researchers looked at the number of additional deaths each month after legalisation, and found there was on average one additional per million residents, in comparison to states that had not changed cannabis laws. The increase was temporary, seeming to last for about a year following legalisation. The combined population of affected areas is 27 million people, suggesting an additional 170 deaths in the first six months after legalisation.

But the study reported the spill over effects to be slightly larger in neighbouring states and provinces, particularly those with population centres closest to the border of a legalising state—possibly because cannabis users were driving interstate to make purchases, before returning under the influence.

It's called 'cannabis tourism', and Monash University's Dr. Tyler Lane says there are important implications for both legalising states and their neighbours as prohibitions against are lifted globally.

"The effect of cannabis legalisation on traffic fatalities is a growing public health concern," Dr. Lane said.

"The results suggest that legalising the sale of cannabis for recreational use can lead to a temporary increase in traffic fatalities in legalising states. This spills over into neighbouring jurisdictions through cross-border sales, trafficking, or cannabis tourists driving back to their state of residence while impaired.

"Our findings suggest that policymakers should consult with neighbouring jurisdictions when liberalising cannabis policy to mitigate any deleterious effects."

Dr. Lane said the findings were in contrast to research on medicinal cannabis suggesting it decreases traffic fatalities.

One reason for the difference may be that medicinal users tend to substitute cannabis for other substances, including alcohol, which has a greater effect on impairment. Recreational users are less likely to substitute and more likely to combine alcohol and cannabis, which has a much bigger effect than either in isolation.

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Citation: Traffic fatalities on a high after cannabis legalisation (2019, February 5) retrieved 14 October 2019 from
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User comments

Feb 05, 2019
One death per million!!!!

How many people die due to overdose of painkillers?????

Big pharma will never let people take their money, they can care less for the population, they prefer them death, or very sad, but they want their money because money buys them everything they need, like porn stars to have sex, cocaine, etc

Feb 05, 2019
How many of those accidents actually involved cannabis? It reads that there were simply more traffic deaths after legalising. There was also an increase of roughly 80,000 people in Colorado just last year. More population would also mean more accidents. This article is completely biased and lacking in scientific credibility. You should be ashamed of yourselves for publishing this.

Feb 05, 2019
Bit hard to put in perspective without knowing what the non-cannibis related fatality rate is... Interesting that the spike fades in about a year? Why?

Might also be interesting to know what effect on non-fatal accidents is. (I'm imagining mellowed out drivers tending to get into more problems at low speed.)

Feb 05, 2019
Did people really believe Marijuana users WOULDN'T drive high? Everyone knew it. They just didn't care. They wanted the high life and the money and that's all that mattered. Anytime you make a mind altering drug more available people will abuse it more. It has consequences.

Feb 05, 2019
Driving at night should be illegal because it causes accidents and deaths.

Feb 05, 2019
anon: The problem is likely this article. Why do they constantly leave important information out?? A cursory search did not find the research this is based on.

Feb 05, 2019
i think its deceptive to say marijuana caused these deaths when at the end of the day it was the individuals decision to get in their car and drive. i don't blame cell phones when someone gets in an accident from texting and driving instead i blame the person who should have known better. i myself am a medical patient and use marijuana 24/7 as a result i do not drive ever, its that simple using marijuana means you do not get to drive and anyone who decided to drive anyways has made a poor decision that is not the fault of marijuana but is instead the result of their own arrogance.

Feb 05, 2019
I wonder how some fundie would feel about being pulled over and asked to take a DRUID test...

Feb 05, 2019
Lol Okay there are severely inaccuracies, un-sourced information, and then the article casually mentions the combinatory factor of alcohol-related collisions, while also briefly dismisses those who use cannabis medicinally and attempts to say that cannabis is an 'alternative' to alcohol???? Suggesting that every medical patient (Cancer, MS, Alzheimers, PTSD, anxiety, etc) is using cannabis as a substitute for alcohol...? What?

Not only does this article fail to quote people and research fully and accurately (or for gods sake even reference MULTIPLE sources to verify information), but it will not surprise you to know that this Monarsh University is not in or near Colorado or any states that have legalization, not even located in Canada, it is located in AUSTRALIA!

Only the finest writing from our friends at MedicalXpress.

Feb 05, 2019
I call fake news on this article. People have been smoking weed and driving for decades, they didn't just now start driving and smoking weed because it was just now legalized. This is another apparent lie spewed out by anti-marijana, Reefer Madness cry babies while they enjoy alcoholic beverages.

Feb 06, 2019
There is actually nothing mentioned of the correlation between the deaths and them being the smokers. This article truly lacks empirical evidence on whether these deaths are because of smoking or other factors. Huge fallacy in this one.

Feb 07, 2019
This article is manipulating the data. For starters it fails to mention that it only increases the 1st 6 months, but has since declined to record lows. Next, it doesn't directly link those fatalities to cannabis, it doesn't report the cause. It doesn't even acknowledge that the populations in those areas increased, ie people new to the area don't know the area and more likely to be involved in a fatal collision.

It is truely important that data not be manipulated to prove a theory. If the entire data as a whole doesn't support your theory, you still have an unproven theory!

Feb 11, 2019
The decline in traffic deaths a year after legalization could be based upon users figuring out dosages from the higher THC strains and timing from edibles. Just as everyone needs to know how alcohol effects them, so to with marijuana.

Feb 11, 2019
The study makes no sense: That cannabis has been legalised does not imply that people are using it more.

So, while there may be a correlation there just can't be causation because in this case the cause would be the legal act of legalising cannabis not it's use as there is just no data about the latter.

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