A new THC breathalyzer has the potential to replace the unreliable sobriety tests that police currently rely on to screen for drivers under the influence of cannabis.

The California based Hound Labs has developed the first breathalyzer capable of measuring the amount of THC in a person's body. And while it has yet to be tested in the field, the device looks like the best screening device to date. That's because when THC is detected in a person's breath, it probably hasn't been that long since they consumed cannabis, according to Mike Lynn - CEO of Hound Labs.

"When you find THC in breath, you can be pretty darn sure that somebody smoked pot in the last couple of hours," Lynn told NPR.

That two-hour window is often considered to be when a person is too high to drive. So the new breathalyzer is much more precise than saliva tests and other methods for detecting cannabis use, which have a much broader timeframe. Meaning THC could be detected long after the effects have worn off.

Take the Draeger DrugTest 5000 for instance. It's the saliva test kit set to be used by Canadian polices forces. It detects cannabis consumption within the previous 6 hours, a time span that is too broad to identify impairment. So a lot of people who are capable of driving safely will probably be taken in for further testing to determine whether or not they should be charged with high driving.

Lynn hopes his device will avoid that situation, which is not only stressful for motorists but also a waste of time for law enforcers. 

"They're not in the business of arresting people that are not impaired when it comes to marijuana. That makes no sense at all," said Lynn. "They're interested in it providing objective data for them at the roadside."

That data has been a long time coming because of difficulties involved in making a cannabis breathalyzer. Unlike alcohol, there is little THC present in a person's breath after they smoke up, Lynn explained.

"THC is something like a billion times less concentrated than alcohol. That's why it hasn't been done before because it's really hard. It's taken us five years to overcome those scientific obstacles."

The Hound Labs breathalyzer will begin trials with real police forces this fall. If successful, it could keep the roads safe while preventing cops as well as cannabis consumers avoid the hassle involved with false positives.

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