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Driving & Cannabis

In Canada, legalization of marijuana has been all the buzz in the media lately. People are realizing the enormous potential of medical cannabis in alleviating pain and nausea, reducing epileptic seizures and helping with many different ailments. With the growing focus on cannabis, one topic that is getting increased attention are the legalities around driving while under its influence. Just to be clear, driving while impaired by alcohol or drugs, including cannabis, is against the law in Canada.

Legislators attempting to create laws to deal with this face a number of challenges, some of which are:

  • Studies are unclear about how marijuana use affects driving
  • Detecting THC levels in urine is easy, but can be detected for weeks, which doesn’t help with a roadside stop
  • Blood tests are more accurate, but are costly and are not appropriate for roadside use
  • Roadside detection methods using saliva are very promising, but are still being tested

Another challenge comes from cannabis users themselves, who may not see the danger of driving while using the drug. Approximately ½ of Canadians who consume marijuana say that it doesn’t impair their ability to drive and actually believe it can make them a better driver.

Researchers into this matter have found a few glaring reasons why drivers should not get behind the wheel after partaking. Studies have shown that after using marijuana, it takes more of your brain to perform simple tasks. This results in slower reaction times, a lack of ability to multitask (very important for a driver) and decreased peripheral vision. Simply put, while intoxicated on cannabis a driver’s ability to react to surprising events on the road is severely impaired. Some estimates say that by driving under the influence, you increase your risk of an accident by as much as 300%.

Statistics back up the research. Impaired driving kills and injures more Canadians than any other crime, and marijuana is second only to alcohol as the drug most frequently found at impaired driving crashes.

What is an Appropriate Limit?

While Canada doesn’t yet have a set limit of intoxication, several U.S. states in which marijuana is legalized have established limits, but they vary from state to state. Some argue that the state imposed limits are arbitrary, not a real indicator of impairment.

A newly-published study found that blood-cannabis concentration is actually not a reliable predicator of impairment. The study found:

  • Drivers under the influence of cannabis performed poorly on walk and turn tests, one-leg stand tests and finger to nose to tests
  • Drivers under the influence of cannabis did not perform worse based on the THC concentration in their blood (with exception of the finger to nose test)
  • There were minimal differences between those with THC levels above or below the five nanogram limit often set in other countries

The study summary stated that differing THC levels affected people in different ways, meaning that a driver with very little THC in the blood could be more impaired than a driver with more THC in the blood.

This makes it very difficult at present to set a reliable number for impairment. To address this some states have adopted a zero tolerance approach to driving while under the influence of marijuana.

The Future of Roadside Testing

In Canada, the RCMP and local law enforcement currently conduct roadside impairment tests for alcohol and cannabis. These tests determine sobriety and whether or not a more detailed test is required.

Looking to the future, three new saliva-based roadside devices are being tested in Canada. More testing, as well as changes to legislation are required before these devices can be used as evidence in court, but in the meantime they are helping law enforcement to determine whether a suspect should undergo additional testing for impairment. Advocates hope that these testing devices will give them the information they need to get impaired drivers off the road as they already are in Europe and Australia.

Changing Perceptions

Public perception of cannabis is changing, that is for certain, as are the laws pertaining to its use. While those changes are likely to be of great benefit to many Canadians there is one change we can collectively agree to right now to ensure that lives are not put in danger: do not drive while under the influence of cannabis.

There are far too many variables involved to say for certain that one person is safe to drive while another is not, to take a risk that might endanger a life. Driving while impaired is always more dangerous than driving sober, and it is the responsibility of all of us to ensure that while we wait for legislation to change we make sure friends and loved ones don’t get behind the wheel after taking cannabis.

Please stay safe on the road.