DUI Tests Inadmissible in Pot Cases, Court Says

DUI Test Cannabis Now

The Massachusetts Supreme Judicial Court issued a ruling that will help protect against false impaired-driving convictions from faulty tests, but will still allow police to work on getting high drivers off the road.


The Commonwealth of Massachusetts saw its highest court rule on Tuesday that roadside field sobriety tests — used to see if someone is under the influence of alcohol while operating a motor vehicle — cannot be treated as conclusive evidence to prove someone is operating under the influence of marijuana.

However, the Supreme Judicial Court did conclude it was fair game for officers to tell jurors how someone performed on the test, but not whether they passed or failed. Police will also not be allowed to tell jurors whether or not they felt someone was too high to be behind the wheel.

“While not all researchers agree, a significant amount of research has shown that consumption of marijuana can impair the ability to drive,” the court said in its opinion. “There is ongoing disagreement among scientists, however, as to whether the [field sobriety tests] are indicative of marijuana impairment. In recent years, numerous studies have been conducted in an effort to determine whether a person’s performance on the [field sobriety test] is a reliable indicator of impairment by marijuana. These studies have produced mixed results.”

The experts tend to agree with the courts on the ongoing complexity of the issue.

“This is one of the more complicated cannabis policy issues out there, and we expect to see a variety of legal, scientific, and technological developments around it over the next several years,” said Mason Tvert, an activist who led Colorado’s successful legalization effort.

Tvert went on to speak of the compelling public interest in preventing impaired driving, but said that many states have adopted laws that result in the punishment of drivers who were not actually impaired.

“Not surprisingly, these flawed laws result in court challenges, leaving it up to judges to keep law enforcement in check, as was the case in Massachusetts,” he said.

The D.C.-based Marijuana Policy Project said it supports the use of field sobriety tests to deal with impaired driving, and noted that the court did not strike down the legality of these tests. “This ruling just says that police officers cannot definitively say if a person failed, so the court must look at the totality of circumstances,” said Senior Communications Manager Morgan Fox. “This could actually protect drivers from being falsely convicted based on one officer’s testimony, but won’t hamper efforts to prevent impaired driving.”

Jolene Forman, staff attorney at the Drug Policy Alliance, says the court’s decision makes a lot of sense because the tests have not been validated. “It’s imperative we invest resources into either validating these tests or finding better tests that actually measure marijuana impairment before we use them to convict people,” she said. “If they’re not actually showing people are who are impaired, we may be falsely charging safe drivers.”

Forman said the tests may also be failing to detect people who are in fact operating a vehicle under the influence of marijuana — as field tests can both under- and over-capture marijuana impairment.

The nation’s oldest marijuana reform group called the court’s decision a common sense ruling. “Available science has never established the predictive validity of Standard Field Sobriety Tests for identifying subjects who may be under the influence of controlled substances other than alcohol,” said NORML Deputy Director Paul Armentano.

Armentano also pointed to the scientific realities of the current state of cannabis testing, or lack thereof: “Given these realities, the court was correct to rule that subjects’ subjective performance on these tests ought not to be viewed as persuasive evidence of cannabis-induced impairment.”

The scale of the problem and value of finding a solution isn’t lost on investors now funding numerous startups looking for a way to test for THC impairment in real-time. Mike Lynn of Hound Labs, one of the companies hoping to invent the pot industry holy grail of a non-intrusive roadside pot test, spoke to Josh Constine of TechCrunch at its annual SF Disrupt conference in San Francisco this week. Constine provided one of the event’s big laughs when he asked Lynn, “Why are you such a narc?”

“I swear I’m not a narc,” the former emergency room doctor Lynn responded. “Really what we try to do at Hound Labs is be fair and balance public safety and fairness. Because we need to have a standard. You can’t go around stoned behind the wheel just like you can’t drive drunk, right? At the same time, you don’t want to start firing people or arresting people that aren’t impaired.”

While Lynn’s hopes of balancing the scales of justice are surely merited, the concept of developing a device that could eventually become standard issue in police vehicles likely isn’t keeping him up at night either.

This year on Saint Patrick’s Day, the San Diego Police Department debut its new pair of Dräger DrugTest 5000s, a mouth swab drug test that can detect seven drugs including marijuana. The test can detect THC, but blood tests would still be required to get exact levels. San Diego’s police chief told the LA Times, “It’s a huge concern of ours with the legalization of marijuana that we’re going to see an increase in impaired drugged driving.”

In Washington, the American Automobile Association (AAA) released a report on the recent climb in road fatalities where marijuana is detected. But AAA conceded it’s difficult to tell if someone is actually driving high.  At the time, the National Cannabis Industry Association’s Deputy Director Taylor West told CNN Money, “All this report really shows is that more people in Washington State are likely consuming cannabis, and thus might have some THC in their systems at the time of an accident. But since having THC in your system tells us nothing about your potential impairment, it would be like a report showing how many people involved in accidents had drunk a beer in the last week.”

In Colorado, police go to a workshop where volunteers get really high and police interact with them. Colorado also released data that showed a rise in traffic deaths where THC was present. But as Tvert pointed out to us earlier this year: “There isn’t very good data pre-legalization.” Tvert said drug testing was done in fewer than 50 percent of fatal accidents, “so state officials have warned against making before-after comparisons.”

TELL US, what should police do to safely protect against high driving?

Jimi Devine has been involved in cannabis reform since 2005 and has worked in the Berkeley cannabis industry since 2009 when he moved to California from Lynn, Massachusetts. Currently serving as Staff Writer here at Cannabis Now, you can also find his writings on cannabis products and policy in the San Francisco Chronicle, The Boston Globe, The Hill, The Chronicle of High Education, GreenState.com, Marijuana.com, 7x7 Magazine, and in Ed Rosenthal's most recent book This Bud's for You. Jimi has a BA in Journalism and Media Studies from Franklin Pierce University.

2 Comments

  1. Greg Howell Basquin

    September 30, 2017 at 1:21 am

    Still abunch of BULLSHITCar’s can drive themselves now ITS a cash grab just like everything else in our society.. And Cannabis is nothing like alcohol

    ABROGATE CANNABIS IN MICHIGAN 2018

  2. Michael Milburn

    September 22, 2017 at 10:48 am

    Hound Labs is just testing exposure to a drug, not actual impairment. Impairment testing is what is needed, and people should not drive if they are impaired.

    I have developed a new public health app that measures actual impairment–it is called DRUID (an acronym for “DRiving Under the Influence of Drugs”) available now in the Apple App Store (Android version coming soon). DRUID measures reaction time, decision making, hand-eye coordination, time estimation and balance, and then statistically integrates hundreds of data points into an overall impairment score. DRUID takes just 2 minutes.

    Our website is http://www.druidapp.com

    DRUID allows cannabis users (or others who drink alcohol, use prescription drugs, etc.) to self-assess their own level of impairment and (hopefully) decide against driving if they are impaired. Prior to DRUID, there was no way for an individual to accurately assess their own level of impairment. DRUID also demonstrates that it is feasible to measure impairment reliably by the roadside, not just exposure to a drug. It could also be a way for cannabis users who have developed tolerance to show they are unimpaired.

    DRUID was featured on NPR’s All Things Considered: http://www.npr.org/2017/01/25/511595978/can-sobriety-tests-weed-out-drivers-whove-smoked-too-much-weed

    Also on television: http://sacramento.cbslocal.com/2017/02/28/science-lags-behind-marijuana-impairment-testing/

    After obtaining my Ph.D. at Harvard, I have been a professor of psychology at UMass/Boston for the past 40 years, specializing in research methods, measurement and statistics.

    Michael Milburn, Professor
    Department of Psychology
    UMass/Boston

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