Marijuana DUI laws are rarely based on scientific evidence

While driving while high on pot is illegal, experts say the prohibition is arbitrary and not backed by science.

While recreational marijuana use is legal in Colorado, the state still prohibits driving while impaired by marijuana. While such a prohibition may sounds like it makes a lot of sense, the fact is that the details of the law are, as Colorado Public Radio points out, arbitrary and based on almost no scientific evidence. In fact, throughout the country states have modeled their marijuana DUI laws on their alcohol DUI laws, which is proving problematic since marijuana does not impair users the same way that alcohol does.

Current Colorado law

In Colorado it is illegal to operate a motor vehicle if the driver has more than five nanograms of THC per milliliter of blood in their body. THC is the active compound in marijuana that makes people feel high. That legal limit is largely based on the similar concept of using a legal limit of blood alcohol content for drivers.

While THC levels alone are not always sufficient to result in a conviction, they can prove highly persuasive for juries and judges. However, basing Colorado's marijuana DUI laws on a legal limit of THC in the bloodstream is beginning to be challenged by both legal professionals and safety experts due to some glaring problems with the legal limit.

An arbitrary level

The fact is that marijuana does not have the same effect on the body that alcohol does. While a certain level of alcohol in one's bloodstream has a fairly consistent correlation to one's level of impairment, for marijuana users THC levels may have only a tenuous relationship to impairment. Frequent marijuana users, for example, may have elevated THC levels hours after consuming marijuana and yet exhibit no signs of being impaired.

In fact, as US News & World Report notes, even the AAA Safety Foundation says that basing marijuana DUI laws on THC levels is arbitrary and has no scientific backing. By criminalizing THC levels, the law may even be violating the rights of citizens. Because elevated THC levels do not always result in impairment, people could find themselves breaking the law without even realizing it.

Criminal defense

As marijuana laws continue to evolve in both Colorado and across the country, it is important for the public to understand what their rights are under these new laws. For those who have been charged with driving while impaired by drugs, for example, it may be possible to fight the charges or get them reduced. An experienced criminal defense attorney can assist defendants and help guide them through what can often feel like a frightening and intimidating experience.