Scientists Need Weed-Smokers br for Research Study As more and more states are legalizing marijuana, scientists have some questions. Researchers at the University of California San Diego The questions are imperative for states, br and users, to understand how long br they should wait to drive after lighting up. Researchers are seeking healthy br adults who have smoked br cannabis previously in their lives. According to the Center for Medical Cannabis Research at UCSD, those br chosen will be asked to smoke pot br and then attempt driving simulations. Participants will also br undergo a performance br assessment on an iPad, measuring br memory, attention and motor skills. 180 people have been recruited for the study so far, but 80 more subjects are needed. This study follows at 2015 study, br suggesting that alcohol impairs br a driver more than cannabis.