When it comes to driving with alcohol in your system, in British Columbia as well as with the rest of Canada, there are certain limits you must stay below in order for it to be legal for you to operate a motor vehicle.
When a person drinks alcohol, with every drink they have, they become more inebriated and as a result, their motor skills degrade. By this we mean, they have less control over their movements, over their words and overall, how they act. When someone is in an impaired state, not only is it dangerous to get behind the wheel of a car, but it is also illegal.
While there is strong evidence linking impaired driving and the increase in crash risks while, the same link cannot be seen when people who tested positive for THC in their system.
In fact, there is evidence that shows people who have tested positive are not even considered to be impaired.
There are two studies that have been done in recent years, testing the effects of marijuana and a person’s ability to function and think properly. These two studies can be categorized as experimental, which focuses on laboratory simulators, and epidemiological, which involves culpability and case control.
In these studies, there were many discrepancies between lab testing and actual crash statistics. In the lab, studies were showing that cannabis did in fact impair a person’s ability to drive and think clearly, however when comparing this to statistics of people who got into accidents and after tested positive for THC, there was no crash-risk increase.
This could perhaps be due to the fact that the period for which you are actually high, which usually lasts only a few hours, is a much shorter time frame than how long the THC will remain in your system.
The effects marijuana usage has on a person will also depend on how often they are using it. Tolerance to its effects will be built over time, and in fact, studies have found that regular marijuana users have the highest degree of tolerance in their cognitive function.
There have also been studies showing that cannabis consumption had little to no effect on hazard-reaction time, speeding, and ‘crash’ rates. The only thing it did have a small effect on was lateral control, meaning steering the vehicle in a straight line.
Misunderstandings of comparing BAC to THC levels
There is a common disagreement and misunderstanding amongst researchers, where some believe that they can link a BAC level to a THC level and the results will be comparable. This is simply not the case. It is much more complicated than that.
When a person consumes alcohol, they tend to become bolder in their actions. They develop a bravado of sorts. This is what has led researchers to understand an increase in accidents when someone has a lower BAC, 0.05 or lower.
While a low BAC level may affect a person’s psychomotor skills, there is no finding that it can be linked to an increased crash- risk.
This alcohol consumption will also have an increased effect on a person’s bravado, and that is likely where the link between increased crash risk and a lower BAC comes from.
Researchers have tried to link a crash-equivalent amount of THC to a 0.05 BAC, but given the fact that a BAC of 0.05 or lower and its effects on motor skills cannot be linked to increased crash risk, it is problematic to compare it to similar THC levels, and beyond that, compare an alcohol-impaired driver to a driver who tests positive for THC.
Alcohol and marijuana affect a person’s body differently and that makes their impact on a person’s ability to drive difficult to compare. It does not make sense to have the legal limit of alcohol in the system coincide with the legal limit of THC when the two things have completely different impacts on a person’s driving ability.
So, the answer to the question this blog post poses is a difficult one to answer, because while driving under the influence of any substance over the legal limit is dangerous, not only to yourself but to fellow drivers, it is also difficult to understand how someone’s psychomotor skills will be affected based on the amount of THC in their system.
And it is even more difficult to compare it to driving while under the influence of alcohol and BAC levels.
If you have been pulled over by the police and are in trouble for driving under the influence of alcohol or drugs, and are confused about what to do, feel free to contact our office, we are always happy to help.
