Rethink that last toke for the road with pot breathalyzers

While nearly a dozen U.S. states allow recreational marijuana, all states prohibit driving under the influence.

But there hasn't been an easy way to prove it.. until now.

Several companies in the United States are preparing to market cannabis breathalyzers...

including Hound Labs in Oakland, California and Vancouver's Cannabix Technologies.

The breathalyzers could detect a user who consumed cannabis within the last few hours, and could be used more broadly by companies not just cops.

Hound Labs Chief Executive Officer Mike Lynn says construction companies could be potential customers.

(SOUNDBITE) (English) MIKE LYNN, HOUND LABS CEO, SAYING:

"Nobody wants a crane operator 50 stories up to be smoking a joint and nor do you want an emergency medicine doctor like myself taking care of a critically ill patient if I were stoned."

But Justin Srekal of marijuana legalization advocacy group NORML says their use could be problematic. Unlike with alcohol, scientific research has not yet established firm correlations between the amount of marijuana one consumes and how impaired a user can become.

(SOUNDBITE) (English) JUSTIN SREKAL, POLITICAL DIRECTOR, NATIONAL ORGANIZATION FOR THE REFORM OF MARIJUANA LAWS (NORML) SAYING:

"My understanding is no company that has claimed that they've cracked the code has put out peer reviewed evidence that shows that there is a correlation between impairment and trace metabolic elements."

Cannabix's THC Breath Analyzer could be cheap enough at a few hundred dollars per unit to potentially allow parents to use them... for those interested in testing their teenager before turning over the keys to the family car.