In our last post, we highlighted the study from the National Highway Traffic Safety Administration that essentially dispelled the myth that drivers under the influence of marijuana are substantially more dangerous than the same people who may be under the influence of alcohol. Basically, there was no statistical increase in risk of a crash associated with marijuana use compared to other drugs, while the risk of an accident caused by alcohol was nearly seven times as high.

We also noted that there was no reliable roadside test that could determine whether a person was legally impaired by marijuana, as opposed to alcohol, but this may change in the future. 

There are companies that are developing what can be called a cannaboid breathalyzer, since it ostensibly would measure THC levels (the psychoactive component of marijuana) which could give a police officer a reading that would measure the level of impairment.

Currently, law enforcement agencies use blood and saliva tests to detect the presence of marijuana in a driver’s system. The problem is that marijuana can stay in a person’s system for a great deal of time, even though they have long since been impaired. As such, these tests cannot reliably determine whether the driver was impaired at the time he or she was behind the wheel. Because of this, drug impaired driving charges may be successfully challenged even if they are lodged along with DWI charges.

It is unclear when the police will begin using marijuana breathalyzers, or what level of THC will be considered legal if and when the devices are used.