Mostly, campaigns to educate the public about drug impaired driving speak to the recreational pot user. Posters hang in dispensaries that warn users about edibles' delayed reaction, and urging people to plan a ride before they're high. The Colorado Department of Public Health and Environment offers guidelines around marijuana use, including suggestions for when it might be safe to drive after consuming cannabis. "As a rule of thumb, if you're smoking, wait at least six hours before driving. If you're ingesting, wait at least eight," their website advises.
But, for daily medicinal users it can be a bit more tricky. The Colorado Department of Transportation says that medical marijuana needs to be treated like any other prescription drug that can impair driving – if a drug causes impairment, it's illegal to drive. Huestis agrees, but notes that guidelines around suggestions for driving for those who use daily is a difficult question to answer. Ultimately, she says, it's something that society is going to have to make a decision on.
Huestis points to the .08 limit in the U.S. for alcohol as an example of a socially acceptable limit, and compares it to most other countries, whose driving thresholds for alcohol are much lower. "With alcohol we're more liberal and we allow for more possibility, but we have more people killed on the roads than almost any other western country."
And yet, companies like Triple Ring Technologies and Hound Labs are still eager to get a product to market. Heanue, of Triple Ring, says that though they're still in the testing phase, his company is hoping to be working with commercial and law enforcement partners in the third quarter of this year. Their technology will be able to detect both inhaled and ingested forms of cannabis in the breath. In an effort to make the detection process less invasive, Hound Labs' is developing a breathalyzer that will be able to detect both THC and alcohol in one instrument.