Though there has been much talk about a cannabis-detecting breathalyzer over the past 10 months, the state of Colorado just took the first serious steps toward making it a reality by awarding a quarter-million dollar grant to Lifeloc Technologies in Wheat Ridge, CO.

Lifeloc, which is one of the leading manufacturers of roadside alcohol breathalyzers used by law enforcement throughout the nation, has a sizable challenge ahead of them. They need to design a device that only detects Delta-9 THC—the psychoactive ingredient that makes a user feel intoxicated.

There are several marijuana breathalyzers currently on the market that detect metabolites of marijuana. These devices are not useful for law enforcement because metabolites are not psychoactive. Other devices on the market try to detect the presence of cannabis by swabbing saliva in the mouth.  This, too, is an ineffective method, as residual cannabis metabolites can stay in one’s system from days to months depending on a user's frequency of use. A Delta-9 THC detector would only be able to detect if someone has consumed cannabis within the past few hours--and how high their psychoactive THC levels are.

"Because [Delta-9 THC] remains in the body for such a short time after smoking or ingesting, perhaps no more than two hours, it's important that we find a way to give law enforcement a tool to detect that at roadside," said Lifeloc CEO Barry Knott in an interview with ABC 7 News.

The $250,000 grant will be disbursed to Lifeloc over the next 3 years. Company representatives have said they will most likely have to sink at least twice that much into research and development. They are currently hoping to have a prototype ready by late 2015.

How Much is Too Much?

The national blood alcohol content (BAC) threshold for a DUI arrest is 0.08%. Earlier this year, Colorado established a similar threshold for THC—5 nanograms. Now all they need to do is figure out a way of measuring that effectively.

As of September, there have been a total of 4,177 DUI-drug citations by Colorado police based on marijuana alone.