AAA Study: Blood THC Levels After Smoking Pot Are Useless In Defining 'Too High To Drive' (arstechnica.com)

An anonymous reader quotes a report from Ars Technica: Blood tests that try to quantify marijuana use are in fact useless at assessing how impaired a driver is, according to a study by the AAA Foundation for Traffic Safety. The study found that people with low blood amounts of THC -- or delta-9-tetrahydrocannabinol, the main psychoactive component of pot -- may still act as if they're really stoned. On the other hand, some people may have THC measurements off the charts yet still act normally. The finding is critical because several states have already set legal limits for the amount of THC a person can have in their blood while driving. AAA concluded that such limits are "arbitrary and unsupported by science, which could result in unsafe motorists going free and others being wrongfully convicted for impaired driving." The conclusion echoes that of other researchers that also noted no correlation between blood THC levels and impairment. Still, there is a need to deter people from smoking pot while driving, AAA argues, as it can impair driving. It recommends that until scientifically valid measures of impairments are put into place, law enforcement should use a combination of behavior and psychological tests to assess whether drivers who use marijuana are safe to drive.

Comments

Re:How about...

[AK Marc]

But you have to draw the line somewhere.

Yeah, you measure reflexes and decision making skills, and take them off the road if they are unsafe.

But doing so would make AARP and voters mad, and we all know stoners don't bother to vote, so you make up arbitrary (and wrong) limits for chemicals, not related to the safety of the driver. Great system.

Re: How about...

[chihowa]

Lane discipline (or a lack thereof) is responsible for most accidents, which is why law enforcement's obsession with speeding is so obnoxious. The fact that police would rather be sitting on the side of the road clocking for speeders (because it's easy and hard to contest in court) and ignoring all of the inattentive drivers changing lanes without looking or signaling, failing to yield the passing lane and encouraging passing on the right, and so on is a damn shame.