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Too high to drive? Legal THC driving limit in Colorado.

On behalf of Dolan + Zimmerman LLP April 29, 2019

While the recreational use of marijuana is legal in Colorado, there are still legal ramifications for driving while high. However, many have concerns regarding the impaired driving laws in the state and question the fairness of these laws.

In Colorado, driving under the influence of of 5 or more nanograms of delta 9-tetrahydrocannabinol, which is more commonly known as THC, can be prosecuted as driving under the influence. This is the primary chemical compound in marijuana responsible for the high users feel.

Unlike with suspected drunk driving, there is no breath test for THC like there is with alcohol. This means that a suspected high driver who chooses to complete a chemical test will need to go down to the police station for a blood test to determine the THC level.

Just like with alcohol though, refusing to take a blood test can result in immediate consequences – such as a mandatory ignition interlock device and alcohol classes. These administrative consequences can happen regardless of whether someone is convicted for impaired driving.

Study calls into question THC level for edibles

One of the issues with this type of blood draw is that there is debate as to what this 5 or more nanogram level means with regard to driving ability and how it will show up in a person’s system.

In a controlled Johns Hopkins University study, participants ate pot brownies and had their blood drawn and tested for THC over the course of a few days. In this study, while the participants showed signs of being high, such as a decrease in coordination and a harder time concentrating, almost 90 percent of people were still under the THC driving limit.

The concern stemming from this study is that someone’s blood levels of THC will react differently based on how someone uses it. Theoretically, this means that someone who smokes marijuana could wind up over the legal limit, while someone who uses the same amount, but in an edible form, would not.

From a user perspective, this also makes it harder to determine when it is safe to drive. Add to this the fact that THC can stay present for days – and even weeks – and one can quickly see how confusing impaired driving laws are when it comes to marijuana use.

Over the limit not a criminal charge requirement

While there is the 5 or more nanogram THC limit in Colorado, this really does not matter, as drivers who are under the 5 nanogram level, or who choose not to participate in a blood test at all, can still wind up facing a driving while ability impaired or driving under the influence charge.

If you’re facing charges related to THC, contact an experienced drug defense attorney in Boulder today.