A marijuana DUI law is in effect in Colorado which sets a legal limit for the amount of active THC in your system while driving. The legal limit is 5 nanograms per milliliter of blood.
One out of every 8 DUI arrests in Colorado now is for marijuana impaired driving.
I know they say it is for the children but in Pennsylvania they DUI checkpoints start around 11:00 PM when the Children are in bed.
Sure, except it turns out the "X nanograms per ml" metric doesn't work...
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. In other words, 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.http://arstechnica.com/science/2016/05/legal-limits-for-marijuana-dui-are-arbitrary-and-unsupported-by-science/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.”