CNN CNN Newsroom January 4, 2014 18:21:00
We're very concerned about possible increase in folks driving under the influence of marijuana. >> so you're concerned about that. does that mean that law enforcement is equipped, prepared, to look for the signs, know when there's probable cause to stop someone. >> that's a great question. it is difficult to know when you're impaired by alcohol or other drugs. the techniques will be used in the same ways. they have to stop people for the same reasons, reasonable suspicion of illegal activity. they have to develop probable cause, based on everything they see at the roadside, talking to the driv...