Authorities say a driver impaired by marijuana caused a July 14 accident in the Bay Area that injured state Controller Betty Yee. When a vehicle driven by an allegedly stoned 25-year-old hit the one Yee was riding in, she passed out. It’s the latest incident to illustrate the absolute need to develop tests that can reliably detect marijuana intoxication. It’s crucial to public safety in the post-Proposition 64 era of legal recreational cannabis use.

Several testing methods have already been developed. Among them are the Dräger DrugTest 5000 machines owned by San Diego police, which use oral swabs to confirm the presence of drugs in the body, with positive results leading to follow-up blood tests. In a recent interview with The San Diego Union-Tribune Editorial Board, Police Chief David Nisleit said he believed it was an effective tool when combined with officers’ observations of drivers suspected of impairment. Canada also recently chose the Dräger machines for national use.

But it is just a matter of time before criminal defense attorneys realize that Dräger also has plenty of skeptics. The Truth About Cars website noted Friday that some authorities in Australia and Ireland have lost faith in the devices’ accuracy and reliability. Closer to home, last year, an official with the Orange County District Attorney’s Office voiced similar concerns, citing unacceptably high numbers of false test results.

Here’s hoping the UC San Diego Center for Medicinal Cannabis Research finds a better way. It’s been tasked by the Legislature to come up with a reliable roadside test for marijuana impairment. Such a breakthrough would make the world a safer place.

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