As state legislators consider adopting a new blood-level standard that would determine who is too high to drive, neither Aspen police nor the Pitkin County Sheriff’s Office could specify whether they have issued any tickets for driving under the influence of marijuana.

Driving under the influence of drugs is just as illegal as getting behind the wheel after drinking, but in the case of pot, it can be difficult to determine who has consumed and how much. However, in the wake of Colorado voters passing Amendment 64 in November, which legalized possession of up to an ounce of marijuana for people over the age of 21, state officials are trying establish a clear protocol for handling stoned drivers.

Pitkin County Sheriff’s Office records manager Charlie Matthews couldn’t point to any DUI-pot charges from the local agency.

“I wouldn’t say it’s so much a policy as that there isn’t a definitive test for being under the influence of marijuana,” Matthews said. “Other agencies may handle things differently, we just don’t see any objective testing for it.”

Meanwhile, the Aspen Police Department doesn’t keep specific records tracking the number of people charged with a DUI for being high, said department spokeswoman Blair Weyer. Sixty-six people faced DUI charges in the city of Aspen last year, but it’s unclear if any of those cases were solely pot related. Ten of those people charged with DUI took a blood test.

State lawmakers are debating setting a blood-level standard for THC, which is the active ingredient in marijuana. A bill that passed the state House Judiciary Committee last week would set the standard at 5 nanograms per milliliter of blood.

If someone is suspected of diving under the influence of drugs, an officer will perform a roadside test to determine impairment. The person also could be taken to the hospital for a blood test. If the driver declines the test, their license will be suspended, according to state law.

In suspected DUI-drugs cases, cops can also call in sheriff’s deputy Levi Borst, who is the upper valley’s only trained drug recognition expert (DRE). Borst spent six months training in 2011 to earn the DRE title.

Colorado began certifying DREs in 1987 and as of 2012 there were 458 DREs in the state, according to the Colorado Department of Transportation (CDOT). State patrol has the most DREs on staff with 54 trained officers.

Borst said he’s been called to a scene because of his DRE certification about seven times. Once there, he performs an evaluation where he systematically examines a person suspected of being on drugs by looking for symptoms that fall into seven broad categories including hallucinogens, stimulants, depressants and narcotics.

Typically when he responds to a call, the driver in question also is exhibiting signs of alcohol intoxication, Borst said. In those cases, officers tend to focus on the booze, since prosecution is much more straight forward for a person who is clearly drunk.

Local attorney Lauren Maytin, who specializes in medical marijuana law, said that she thinks cops are more aware of people driving high since weed was legalized in November.

Currently, if a driver submits to a blood test for being stoned and is charged with a DUI based on that information, there is legal room to argue that they weren’t impaired, she said. That could soon change, however, if the Legislature passes the pot-DUI bill.

The proposed 5 nanograms standard isn’t necessarily fair, because patients who have been on medical marijuana for a long time can still have a lot of THC in their blood and not be impaired, Maytin argued.

“We all know there are people who can have that in their system and have absolutely no impairment,” Maytin said. “ ... It’s kind of a strange predicament.”

Since Amendment 64 became law, Borst said he hasn’t seen an increase in the number of instances of people driving high. Still, he considers driving stoned a problem in the valley.

“I think that anything that people take to get impaired has a carry-over effect on how safely people can drive,” Borst said. “I think that’s true in terms of alcohol, marijuana, ecstasy, cocaine or [painkillers].”

In the past year, Borst has evaluated stoned drivers who pull out their medical marijuana license as a defense for being high, he said. That is still not acceptable, because it’s like driving on hydrocodone after surgery.

“Just because you have a prescription for it ... doesn’t mean you can get out of surgery all doped up and drive your car home,” he said.

Borst agreed that it is difficult to pinpoint a specific THC level that would indicate impairment. For some people, smoking a little bit can impair their driving while for others, who regularly consume marijuana products, their driving ability may not be impacted as much, he said. As a DRE, it’s a difficult issue for Borst to wrap his hands around, he said.

“It’s one of those infinitely complex issues that we’re just beginning to scratch the surface of,” Borst said.