For police and pot smokers, traffic stops pose a huge problem. There’s no quick way to tell if a driver is high — whether they ingested pot a couple hours ago, or last week.

But an Oakland startup claims its new technology, announced Wednesday, will enable law enforcement to immediately detect and measure current levels of THC — the active ingredient in marijuana — by sampling a couple of breaths.

Developed at UC Berkeley, trials on Hound Labs’ new technology will begin early next year at UC San Francisco. That’s when Alameda County sheriff’s deputies will begin carrying prototypes of the firm’s handheld device to conduct voluntary roadside tests.

If it works — and receives Food and Drug Administration approval several years down the road — the gadget could prove quite profitable considering there are more than 12,000 local law enforcement agencies to count as potential customers in the United States alone.

Creating a Breathalyzer for pot could be the first step toward remedying one of the biggest issues facing marijuana advocates and law enforcement.

Unlike with alcohol, there’s no standardized system to measure marijuana impairment.

Tests that promise immediate results are cumbersome, and those that rely on metrics like blood, urine or saliva take longer to process. They can also detect pot usage from weeks earlier — implicating people who haven’t smoked in days. Medical marijuana patients who ingest cannabis regularly are at particular risk for testing positive — even when they’re not intoxicated.

“If they have a test like that, it would help both ways,” said retired California Highway Patrol Commissioner Dwight “Spike” Helmick, who has discussed the technology with Hound Labs CEO Mike Lynn. “It would help law enforcement and it would let a lot of people off the hook who may not have been under the influence when they were pulled over.

“By measuring the amount of THC in breath, we can focus on people who are impaired,” Lynn said.

“We hope that eventually this will start a national dialogue,” said Lynn, a former venture capitalist who is an emergency room physician at Highland Hospital in Oakland and a reserve officer in the Alameda County Sheriff’s Department.

That conversation could start soon as several companies are working on technologies to address drugged driving. So far, however, there has not been a lot of venture capital moving toward this corner of the cannabis world. But technology breakthroughs could spur more investment, experts said.

“This is an industry that is growing at a rapid clip — and this is a pain point for it,” said Troy Dayton, CEO of ArcView, whose investor group has put $59 million in 93 cannabis-related companies. “And whenever you have a pain point that can be solved with technology, there is going to be a lot of money headed that way.”

Hound Labs’ technology focuses on breath. It seeks to determine whether someone has smoked in the past two or three hours. (One thing the technology so far can’t determine is THC levels in a person who consumed edible cannabis.)

“There is very little in the scientific literature on THC and breath,” said Kara Lynch, a professor at UCSF, who will be the principal investigator on the study, which will be done on 20 medical marijuana patients early next year. She hopes to have some early results by spring.

There’s reason not to get overly excited about the technology, cautioned Andrea Roth, a professor of law at UC Berkeley who has written extensively about impairment testing. The development needs to be accompanied by studies of marijuana’s effects on driver impairment, including road tests.

Because alcohol and cannabis behave so differently on the human body, states considering legalization shouldn’t just adapt the blood-alcohol scale to measure cannabis impairment, Roth said.

Still, a standardized test could be a catalyst in softening opposition to marijuana legalization nationwide, she said.

“For many people out there, the concern about drugged driving is one of the main political hindrances to supporting legalization,” she said. “And I think anything that could be seen as a legitimate way of dealing with DUI-marijuana can only help the legalization movement.”

Joe Garofoli is a San Francisco Chronicle staff writer. E-mail: jgarofoli@sfchronicle.com Twitter: @joegarofoli