How high is too high? Colorado struggles to test marijuana impairment for drivers
STEAMBOAT SPRINGS — In 2014, when recreational marijuana became legal in Colorado, Matt Karzen, an assistant district attorney in Routt County at the time, noticed a lot of criminal cases coming to his office involving drivers arrested on suspicion of driving stoned.
It was the first time such cases had gone through local justice system under the laxer laws, and he was not sure how they would play out in court. So, his office brought a case in front of a jury as a sort of litmus test for convicting high drivers.
The case involved a man pulled over in Steamboat Springs for having a dirty windshield. It started as a routine traffic stop for driving with obstructed vision, but law enforcement officials noticed the man behaving strangely. Resulting tests showed he did not have alcohol in his system, but he was over the legal limit for marijuana.
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When jurors reviewed body camera footage and reports from law enforcement, they weren’t convinced the tests proved beyond a reasonable doubt the man was impaired.
“The guy was acquitted in about five minutes,” Karzen said.
As marijuana becomes more widely used across the state, much uncertainty remains about how the drug impairs the body and at what point someone becomes too high to drive. A lack of clarity and research has made it difficult for law enforcement officials to test for marijuana impairment during traffic stops and for the courts to convict people accused of driving high.
According to current state law, people can be prosecuted for driving under the influence if their blood contains more than 5 nanograms of active tetrahydrocannabinol, or THC, the cannabinoid in marijuana that causes its coveted psychoactive effects.
But marijuana users, particularly those who partake regularly for medicinal purposes, worry they would test over the legal limit, even when they are not impaired.
Trends in marijuana use
A recent report from the New York Times investigated the legacy of the last five years of legal marijuana in the state and found, more than anything, the drug has become a more commonly accepted part of life for Coloradoans.
About twice as many residents smoke marijuana compared to the rest of Americans.
During a June session of the Steamboat Springs Police Department’s Citizens Academy, which teaches the public about the work of local law enforcement, officers said they have spoken with many people who think it is OK to drive stoned. This worried officer Lisa Wilson, who does not want a lower perceived risk to cause accidents.
As she explained, “If you feel different, you drive different.”
According to a 2018 study from the Colorado Department of Transportation, the number of highway deaths involving drivers with marijuana in their system has nearly doubled since legalization, with 75 deaths in 2014 and 139 in 2017.
But, the number of drivers involved in a fatal crash who tested over the legal limit for marijuana — that 5-nanogram threshold — has decreased sharply in recent years. In 2017, 35 drivers in such accidents were over the legal limit, down from 52 in 2016.
As the study advises, “The presence of a cannabinoid does not necessarily indicate recent use of marijuana or impairment.”
Cannabinoids have a stubborn way of sticking around in people’s fat cells, meaning someone could test positive for the drug, even over the legal limit, days or weeks after they smoked. This is especially true for frequent users.
“People can be heavily saturated with THC in their system and not be under the influence,” Karzen said.
Concerns among marijuana users
Larisa Bolivar admits to using marijuana almost every day. The executive director of the Cannabis Consumer Coalition, based in Denver, Bolivar has been an advocate for the drug long before it became legal.
The Washington Post, in a 2014 article, called her “one of the city’s most well-known proponents of decriminalizing marijuana nationally.” In 2004, she visited Steamboat to advocate for a cancer patient who was facing charges for using medical marijuana, which was legal at the time.
Fifteen years later, she is seeing a similar, enforcement-heavy approach to nabbing people suspected of driving high, despite a lack of certainty for testing impairment.
As Bolivar explained, many marijuana users, especially those consuming it daily and at higher doses for pain management or other medicinal purposes, will have large amounts of THC in their blood but not feel or act impaired.
“I haven’t consumed (marijuana) today, but I can guarantee you I have more than 5 nanograms in my system,” she said.
As someone who drives on a regular basis, Bolivar is always concerned she could be cited for a DUI even if she does not feel or act impaired.
“That is a very scary thought, and it’s totally unfair,” she said.
Sobriety tests for marijuana
Local law enforcement officials tend to agree with people like Bolivar, arguing the current science on marijuana impairment often does not reflect reality. Nor do they see it as a new issue.
“This challenge has been around as long as cannabis has been consumed,” Steamboat Springs Police Chief Cory Christensen said of measuring a person’s intoxication.
As he explained, field sobriety tests for alcohol have been researched and standardized over decades. Dating back to 1977, the National Highway Traffic Safety Administration has honed the tests to such an extent that recent studies report accuracy of 91% to 94%.
“We have a lot of experience with drunk drivers,” Christensen said. “We know what that person looks like, and you can smell it.”
Much less researched and certain are sobriety tests for marijuana. Law enforcement officials usually employ two methods to test for any kind of drug impairment. One way is to ask the driver to undergo a blood test to determine if they are over the 5-nanogram limit.
Some agencies also have drug recognition experts who have been trained to evaluate a driver for substance impairment. Several local troopers with Colorado State Patrol have the certification and are able to assist other law enforcement officials with roadside sobriety tests specific to drugs. Many of the criteria for impairment seem similar to alcohol, such as the one-leg-stand test.
Other considerations, such as redness in the eyes, could be the result of other, non-drug related conditions, like allergies or irritation.
“There is no go-to tool that is considered reliable across the board to determine if someone is impaired by marijuana,” Karzen said. “Right now, we’re just stuck with body camera footage and an officer’s assessment.”
Most such cases result in a plea deal, according to Karzen. Drivers usually plead guilty to driving while ability impaired, or DWAI, which is a traffic infraction — not a crime. It typically results in a fine and the revoked driving privileges for 90 days, a laxer sentence than for DUI offenses.
In many instances, people suspected of driving under the influence of marijuana also have an illegal amount of alcohol in their system, according to Karzen. If that is the case, prosecutors typically pursue a DUI conviction solely for alcohol because jurors feel better-versed at recognizing when someone is drunk.
Need for new tests and laws
What all of this points to is a need for more accurate measures of marijuana impairment, something state lawmakers are trying to accomplish through legislation.
One bill proposed during the 2019 Legislation Session would have thrown out the 5-nanogram threshold and given law enforcement full discretion in determining impairment through field sobriety as well as blood tests.
It faced strong backlash before lawmakers postponed it indefinitely in February.
Complicating the issue is the fact that marijuana is still federally illegal, so conducting accurate, legal research on how the drug affects the body has proven difficult.
With no changes for the foreseeable future, Karzen has been advising prosecutors in his office to be prudent in pursuing DUI convictions for marijuana, and to limit convictions to cases in which people showed obvious signs of impairment.
“I’m very uncomfortable proceeding with a criminal prosecution on impaired driving based only on the 5-nanogram limit,” he said.
For an example, he alluded to a scene in the cult classic, “Cheech and Chong’s Up in Smoke,” in which the two, red-eyed stoners get pulled over after smoking a joint the size of a salami.
Karzen chuckled at using such a reference, but those clear indications — poor driving, memory loss, marijuana smoke billowing from the windows — “those are what our prosecutors look for,” he said.
Christensen’s officers have a similar policy.
“If drivers don’t demonstrate any signs of impairment, we don’t take any action,” he said.
Regardless of the lack of clarity on marijuana impairment, people still have an obligation to drive sober.
“There is no excuse to drive impaired in any way,” Christensen said.
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