Stoned drivers are a lot safer than drunk ones, new federal data show

http://www.washingtonpost.com/blogs/wonkblog/wp/2015/02/09/stoned-drivers-are-a-lot-safer-than-drunk-ones-new-federal-data-show/?tid=rssfeed

Several states have passed laws attempting to define “marijuana-impaired driving” similarly to drunk driving. Colorado, for instance, sets a blood THC threshold of 0.5 nanograms per milliliter. But that number tells us next to nothing about whether a person is impaired or fit to drive. The implication is that these states are locking up people who are perfectly sober…