AdvertisementThe Difficulty Of Enforcing Laws Against Driving While High03:25Download AudioResumeSeptember 06, 2016Ben Markus, Colorado Public RadioStephanie O'Neill, KPCCfacebookEmailAbby McLean of Northglenn, Colo., stands near the stretch of U.S. 85 in Adams County where she was pulled over for a DUI check in September 2014. (CPR News)