Puff, puff, pass that bill. Federal authorities want to know how stoned is too stoned for drivers, according to a provision in the recently signed Federal Highways Bill.

The new law directs U.S. Department of Transportation Secretary Anthony Foxx to study the effects of marijuana on drivers and present those findings to Congress by the end of 2016.

As more states legalize marijuana — Oregon and Alaska joined Washington and Colorado with legal pot, and 12 states have decriminalized possession — Congress asked the department to determine how to train police to spot stoned drivers and how to test them.

According to a Gallup Poll this year, 47 percent of American surveyed said they thought marijuana would make the roads less safe in states with legalized cannabis. (Read More…)