The California legislature is actively considering a per se law that would criminalize driving with a certain THC level in your system analogous to the laws we currently have regarding alcohol. This is true despite the fact that the scientific evidence is anything but conclusive when it comes to marijuana and driving.
Cognitive Studies
One area of agreement among those who have explored this issue, as reported in a National Center for Biotechnology Information study, is that marijuana does measurably impair every performance area that can reasonably be connected to driving a motor vehicle. Among the performance areas studied were motor coordination, tracking, visual functions and complex tasks that involve divided attention. Based on this information, it seems logical to conclude that smoking marijuana increases the risk of being involved in a car accident. However, that may not be the case.
Driving Studies
In actual road tests, drivers considered to be intoxicated on marijuana exhibited only modest driving impairment, and regular users who drove on a set course showed almost no functional impairment. In attempting to explain this seeming contradiction between cognitive impairment and functional driving, researchers have focused on the typical marijuana user’s awareness of impairment.
As contrasted with an alcohol user, a marijuana user overestimates his or her level of impairment. Therefore, the average smoker will drive slower, tend not to overtake other vehicles and maintain greater following distances. Drinkers, on the other hand, perceive themselves as less impaired than they actually are and the opposite driving behavior is more often observed.
THC Blood Levels
THC levels tend to peak quickly after inhalation and decrease rapidly, which makes it extremely difficult to extrapolate backwards from the time a suspect’s blood test was taken to the time of an accident, for example. Additionally, measureable amounts of THC can remain in your system for up to seven days, especially for regular users. Despite the science, 18 states have per se laws regarding THC as follows:
- Nine states have zero tolerance for THC or metabolites, which are compounds that are produced in the body by the synthesis of a psychoactive substance, but they are not themselves psychoactive.
- Three states have zero tolerance for THC but no restrictions on metabolites.
- Five states have specific THC limits
- One state has what is called a reasonable inference law for THC.
Most Los Angeles and Orange County DUI attorneys predict California will soon join this group of states in one form or another.
