In keeping up with the times, a California company has developed the first-ever breathalyzer machine that screens motorists for both alcohol and THC content. The new device, which is expected to be carried by law enforcement personnel in states where weed is legal, will be a welcome relief for officers, who have had a difficult time determining whether pot smokers were too impaired to drive. Previously, it was difficult to detect the presence of THC in breath; and hair, blood and urine tests go back too far in a user's history, making them useless in determining whether a person smoked just before getting behind the wheel, says Dr. Mike Lynn. "If we find THC in breath, it means the person smoked in the last couple hours," Lynn says. Hound Labs, which developed the technology, recently secured $30 million to fund an expedited rollout of the new breath testing device, the company reports. It's expected to be in the hands of law enforcement agencies by the end of the year. Can two people smoke the same amount of weed, but not be equally affected by it? Is driving on weed as dangerous as driving drunk?