As I’ve posted often in the recent past, with the increasing use — and legalization — of marijuana, legislators and law enforcement are falling over themselves trying to come up with answers to many uncomfortable questions, such as:
Does marijuana, in fact, impair driving ability?
How does an officer detect recent use of marijuana in the field?
How do you measure the amount of active marijuana (THC) in the body at the time of driving?
At what level of active ingredients in the body is a person impaired?
How long do measurable amounts of marijuana stay in the body?
If impairment levels cannot be determined, is there an illegal per se level that can be used, such as .08% with alcohol?
And as I’ve posted in the past, there are no accepted satisfactory answers to these and related questions. See, for example, California Law Attempts to Prevent Marijuana Use While Driving, Is it Possible to Prove "Driving Under the Influence of Drugs? and Legal Defenses to a California DUI of Marijuana.
Unlike with alcohol, the various states have taken a variety of different approaches to criminalizing marijuana and driving. See What Are Your State’s Drugged Driving Laws? One recent and growing approach is to simply create so-called "per se" laws which criminalize driving with specific levels of THC in the blood, regardless of impairment. This was recently considered by the Oregon Legislature, resulting in the following Oregon House Bill Legislative Report, excerpts of which follow:
Salem, OR. Dec. 31 — …While Colorado and Washington, the first states to legalize recreational marijuana, instituted a per se THC blood concentration limit of 5 ng/ml, Oregon did not. Instead, Oregon relies on evaluations by Drug Recognition Experts (DRE) to assess drivers for intoxication if they have already passed a breathalyzer test (i.e. have blood alcohol content below 0.08)….
Differences in how the body processes marijuana as compared to alcohol makes accurate detection of THC concentration and its intoxicating effect significantly more difficult. It is especially difficult to detect recent use of marijuana in the field…
Due to restrictions on cannabis research and limited data, it is difficult to make definitive statements about the risk of THC-intoxicated driving. The body of evidence that does exist indicates that while attitudes towards driving after marijuana use are considerably more relaxed than in the case of alcohol, the risk of crashes while driving under the influence of THC is lower than drunk driving. Little evidence exists to compel a significant change in status quo policy or institute a per se intoxication standard for THC.
While the confusion, floundering and passage of inconsistent laws continue, so do the arrests and convictions of innocent drivers.