Recreational Marijuana Is Legal In California, But Stoned Driving Is Still Hard To Detect

Photo Credit: Justin Sullivan

When a 22-year-old Hayward man allegedly slammed his Cadillac into a California Highway Patrol vehicle and killed Officer Andrew Camilleri on Christmas Eve, he was under the influence of alcohol and marijuana, officials said.

CHP reported that Mohammed Abraar Ali had a blood-alcohol level of .11, above the state limit of .08 for motorists. While it’s not clear how the agency documented Ali’s cannabis consumption, he said he got high at a Christmas party, authorities said.

Proving intoxication from weed is more difficult than it is with alcohol, as law enforcement does not have a device like a breathalyzer for alcohol. Without such a tool, law enforcement must rely more on roadside sobriety tests.

These are the same tests used for drunken drivers: walking a line and tracking the movement of an officer’s finger, among others. While CHP officials say the tests have been effectively used to detect stoned drivers for years, experts have pointed out that some judges and prosecutors are less comfortable with the subjectivity of them.

For public-safety officials, Camilleri’s death heightened concerns about the dangers of driving under the influence of marijuana, in part because it happened just days before California started allowing retail cannabis sales to adults 21 and over. The death revived calls for stronger laws governing stoned driving.

Officials from CHP and the state Office of Traffic Safety have said they worry that legalization will lead to an increase in stoned driving, pointing to statistics in Colorado that showed an uptick after the state allowed recreational marijuana sales in 2014.

But California for now will not be able to precisely measure if retail marijuana sales have the same effect because CHP doesn’t distinguish between marijuana and other substances when arresting suspects for drugged driving.

Several states, including ones that legalized marijuana before California, have sought to toughen stoned driving laws by setting limits on the amount of THC that can be in the body. THC is the active compound in marijuana. Similar proposals have so far been unsuccessful in California.

Thomas Marcotte, who is leading research into stoned driving at the University of California, San Diego, cautioned lawmakers against taking that approach until research and technology catch up.

“Right now, I don’t think the science is there to back it up,” said Marcotte, a researcher at the school’s Center for Medicinal Cannabis Research.

Without an approved breathalyzer for marijuana, police sometimes use blood tests. But they have not been proven reliable, and some suspects have been found to have low levels of THC despite obvious signs of impairment, Marcotte said.

Conversely, other suspects who regularly consume marijuana may have large amounts of THC stored in the system, yet display little or no signs of impairment, Marcotte said.

The National Highway Traffic Safety Administration and transportation associations have reached a similar conclusion about laws based on THC limits.

Such laws “imply a relation between drug concentrations and impairment. The scientific consensus is that the evidence to establish these relations does not exist,” according to a 2017 report by the Governors Highway Safety Association.

Without an established measurement for marijuana impairment, law enforcement agencies have relied on a program to train officers how to evaluate signs of stoned driving. The program was started by the Los Angeles Police Department in the 1970s before it was taken over by the International Association of Chiefs of Police and NHTSA. The program trains officers to become experts in recognizing the symptoms of a range of drugs.