Small bag of marijuana

The legalization of marijuana is slowly but surely making its way across the country. At the beginning of 2018, recreational marijuana becomes legal in California. Law enforcement agencies in that state and throughout the U.S. are understandably concerned that they don't have the kind of equipment like a breathalyzer that registers blood alcohol content to determine the amount of marijuana in someone's system.

The Effects of Marijuana on Drivers Are Unpredictable -- and Potentially Deadly

Marijuana's impact on people is far more complicated than alcohol's. A regular marijuana user may have built up enough of a tolerance to smoke a joint and drive without impairment. A rookie user may take one puff and be unable to drive safely. Beyond that, traces of marijuana can remain in people's bloodstream long after they can feel the effects.

It's never wise to drive after ingesting any amount of marijuana. The consequences can be deadly. In 2015, over a third of drug-related fatal crashes involved marijuana. However, how do police officers determine at the scene whether a driver is impaired by the drug and, therefore, whether he or she should be arrested? As one California Highway Patrol officer acknowledges, determining who to arrest is often a "judgment call." He agrees that "we want our officers only arresting people who are impaired."

Could a Roadside Tablet Test Be in the Future?

University of California San Diego researchers at the school's Center for Medicinal Cannabis Research are testing subjects using a simulator to determine how marijuana impacts their driving. Some subjects smoke a real joint, while others are given a placebo. They then get behind the wheel in a simulated driving situation.

Researchers look at things like how they respond to a yellow light and deal with off-ramps. The latter is a problem for many who are too stoned to drive, according to police. They also measure their subjects' multi-tasking skills and memory. They're hoping to create a roadside tool like a test that drivers can take on an electronic tablet.

As the center's co-director says, "The ultimate outcome is to see whether or not we can really help law enforcement separate those people who are impaired due to cannabis or those people who may have cannabis in their system and are not impaired."

The more drivers who are impaired, whether by alcohol or drugs, who can be kept off the roads, the better. However, those who are injured in a car crash caused by a driver who may have been under the influence of something have the right to the truth and possibly to seek compensation from that driver in civil court, regardless of any criminal penalties the at-fault driver may face.