Come November, Californians may be voting on whether to legalize recreational marijuana and there's a lot to consider on that front, including issues of public safety, like driving.

We have tests in place to determine whether someone has been drinking too much alcohol to drive, but what about driving while high? 

Turns out that's a bit trickier to measure, but that's not stopping a group of researchers at UC San Diego from trying. Associate physician Barth Wilsey is involved in the project and he joins Alex Cohen for a discussion on the matter.