[Cecil Terwilliger]

Interesting article on driving while high. I'll be honest part of the reason I'm posting, other than it is relevant, is that it follows exactly what I've been preaching for years regarding driving while high.

Nine states, including some that have legalized marijuana for medical use, have zero-tolerance laws for driving and marijuana that make not only any presence of THC in a driver's blood illegal, but also the presence of its metabolites, which can linger in a driver's bloodstream for weeks after any impairment has dissipated.

That makes no sense, said Mark A. R. Kleiman, a New York University professor specializing in issues involving drugs and criminal policy. "A law against driving with THC in your bloodstream is not a law you can know you are obeying except by never smoking marijuana or never driving," he said.

The problem is that determining whether someone is impaired by marijuana, as opposed to having merely used the drug, is far more complex than the simple and reliable tests that have been developed for alcohol impairment.

The degree to which a driver is impaired by marijuana use depends a lot on the individual, the foundation said. Drivers with relatively high levels of THC in their systems might not be impaired, especially if they are regular users, while others with relatively low levels may be unsafe behind the wheel.

In addition, frequent marijuana users can exhibit persistent levels of the drug long after use, while THC levels can decline more rapidly among occasional users.

Studies show that using marijuana and driving roughly doubles the risk of a crash, Kleiman said. By comparison, talking on a hands-free cellphone while driving — legal in all states — quadruples crash risk, he said. A blood alcohol content of .12, which is about the median amount in drunken driving cases, increases crash risk by about 15 times, he said.

Driving with "a noisy child in the back of the car" is about as dangerous as using marijuana and driving, Kleiman said.

http://www.azcentral.com/story/news/...oned/84190832/