02/29/2012 02:43 pm ET Updated Feb 29, 2012

Drugs & Driving More Fatal Than Drunk Driving In California (VIDEO)

Friends don't let friends drive… drugged.

While drunk driving has been on the decline, drug-impaired driving has increased over at least the past four years, according to figures released Tuesday by the California Office of Traffic Safety.

Three out of every 10 people killed on California roads in 2010 tested positive for legal and/or illegal drugs, according to the news release.

Drivers high on prescription drugs, marijuana or other drugs often go under-reported because drug testing is expensive and there is no established legal limit.

Chris Cochran, spokesman for the Office of Traffic Safety, said, “We’re sort of where we were with drunk driving in 1950. We’re just getting a handle on it,” the Los Angeles Times reports. Cochran also told the Times that he thinks that increases in legal marijuana and prescription drug use are likely contributing to the problem.

In response to the issue, the Office of Traffic Safety and the California Highway Patrol have trained over 700 police officers in the past five months to detect and apprehend drug-impaired drivers. Police departments throughout the state have also sent officers to advanced drug recognition program to become Drug Recognition Experts, the news release explains.

The problem remains a difficult one to remedy, however, without a legal toxication standard. While some have called for a national legal marijuana toxication limit, there is disagreement about how much pot it takes to impair a driver, as FOX reported in the video below. Others say that an officer's case-by-case judgment is better than a one-size-fits-all legal limit.