Finland’s highest court has ruled that motorists are unlikely to get slapped with a driving under the influence charge if they drive days after using marijuana.

The Finnish Supreme Court determined that the DUI laws still need legislative action in order to sort out the gap between when the psychoactive effects of cannabis subside, and how much longer using it leaves a so-called “fingerprint” in your blood sample.

Here’s how the Finnish news service Yle News breaks it down: “Cannabis usage leaves a substance known as tetrahydrocannabinol or THC in the body, prompting the production of a metabolite, carboxytetrahydrocannabinol (THC-COOH), where a metabolite is a substance required for or produced from metabolism.”

But while THC typically exits the body within hours of usage, THC-COOH, which does not yield any intoxicating effects, can linger in the system for days or even weeks.

Finnish police have been known to issue DUI charges when THC-COOH is found in the blood.

According to Yle, the Finnish Supreme Court addressed this matter a few years back, when it dismissed the conviction of a driver who had smoked marijuana before driving, ruling that THC-COOH “does not affect the ability to drive nor endanger traffic safety even at high levels.”

But despite that ruling, some Finnish law enforcement officials have continued to write DUIs in those circumstances, as the country’s code requires citations if drivers have “an active substance or metabolite of a drug used” in their blood.

“It’s quite rational that finding it several days after use would not lead to a drunk driving penalty because it does not affect the ability to drive,” said Teemu Gunnar, a forensic toxicologist with the National Institute of Health and Welfare in Finland, as quoted by Yle.

Recreational marijuana use remains illegal in Finland, though it is available to treat certain medical conditions. According to Yle, cannabis metabolites were the second-most-frequently found substance in Finnish DUI cases last year that were caused by drug use, with records showing 1,784 hits of THC in lab samples and 3,794 of THC-COOH.

It’s something that American law enforcement is increasingly grappling with on U.S. roads, too. A survey released in June by AAA found that almost 70 percent of Americans believe it is unlikely for a driver to get busted by the cops while high on marijuana, and reported that roughly 14.8 million drivers had gotten behind the wheel within an hour of using pot in the last 30 days.