Police officers will normally investigate a “Marijuana DUI” by calling an officer to the scene of the traffic stop who is a “Drug Recognition Expert” or “DRE.” This officer will conduct Field Sobriety Exercises to attempt to determine the driver’s impairment. Ultimately, if an arrest is made a blood or urine sample will be taken and tested for the presence of THC.
The problem is that determining whether someone is impaired by marijuana, as opposed to having merely used the drug, is far more complicated than showing whether someone is impaired due to the use of alcohol.
In February 2015 the National Highway Traffic Safety Administration (NHTSA) released the results of “the first large-scale [crash risk] study in the United States to include drugs other than alcohol,” which it described as “the most precisely controlled study of its kind yet conducted.”
The researchers found that, after controlling for various factors, a detectable amount of THC, the active ingredient in pot, in the blood did not increase the risk of accidents at all. Having a blood alcohol level of at least 0.05 percent, though, increased the odds of being in a crash by 575 percent.
Although chemical tests (like blood tests and urine tests) can show the presence of marijuana in your system, there currently is not a scientific consensus about what level of THC in your system means you are impaired.
Also, there is a huge problem in that THC can remain in your system for a long period of time after it is no longer psychoactive or having an effect on your system. For example, a chronic user of marijuana may have a positive test days or even weeks after their use. Unlike alcohol, it is extremely difficult to take the results of a positive THC and then extrapolate back in time as to the amount and recency of use.
It is anticipated that after Prop 64, there may be newer and more accurate testing devices developed or additional training that more accurately shows marijuana impairment for DUIs. For now though, “Marijuana DUIs” should be regarded as suspect and an experienced “Marijuana DUI” attorney should be hired to fight them.Back to Marijuana Law Practice Area