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Roadside Drug Tests: Failed Technology From the Failed War on Drugs

by Anthony Accurso

Field test kits are touted as an easy way for law enforcement to determine if an unknown substance is in fact a narcotic. Millions are used each year by police during traffic stops, so they are commonly referred to as “roadside drug tests.” But revelations about the accuracy (or lack thereof) of these tests have called into question their usefulness for law enforcement purposes, causing a push to reform their role in prosecutions and elsewhere.

On the last day of 2015, Dasha Fincher was arrested in Monroe County, Georgia, during a traffic stop. Fincher was a passenger in the vehicle, and officers found an unknown substance attributed to her during a search. Deputies used a roadside drug test kit which indicated the substance contained methamphetamines. She would spend the next three months in jail on a $1 million bond because of the suspicion that she was a drug trafficker, largely based on the roadside test.

A subsequent lab test would reveal the substance was actually cotton candy. Though there were several reasons why the system failed Fincher, much of her trouble stemmed from the field test kit which misidentified a harmless substance as a narcotic.

A Known Problem

The Clark County District Attorney’s Office in Las Vegas filed motions in March 2017 to vacate and dismiss charges against five defendants convicted of possessing small amounts of cocaine between 2011 and 2013. According to ProPublica, “[a]ll of the defendants, facing possible jail time, pleaded guilty to drug charges. One of the exonerees was sentenced to eight months,” and “[t]he other four received community service or left the state before sentencing.”

In 2010, the Las Vegas Police Department’s crime lab pushed to have the department abandon the test kits used to detect methamphetamine and cocaine. A 2014 report submitted to the U.S. Department of Justice – as part of a federal grant – “detailed how the kits produced false positives.”

The crime labs director, Kim Murga, said in 2016, we “don’t turn a blind eye” to the risk of false positives in these kits, but she also “acknowledged the lab had not tried to more effectively eliminate errors,” according to ProPublica.

This problem isn’t unique to Las Vegas. The National Registry of Exonerations recorded that “[c]ourts have overturned 131 drug convictions in the past 10 years after laboratory analysis determined the alleged drugs were legal substances.”

Other counties have begun looking at the integrity of convictions carried out in their jurisdiction. Houston overturned approximately 250 such convictions. Reporters with the Fox 5 investigation team reviewed Georgia police records from Monroe County and “found that at least 145 people were wrongly charged with felonies after a field test falsely claimed they had drugs.”

“Instead of ecstasy, cocaine, or methamphetamines, people jailed actually had common items like incense, headache powder or cleaning supplies,” reported Fox 5.

The Safariland Group is the largest manufacturer of field test kits and produce the brand of kits used by the Las Vegas police. The company told ProPublica in 2016 that “field tests are specifically not intended to be used as a factor in the decision to prosecute or convict a suspect.”

During a 2017 court hearing, a company representative testified that it keeps a list of 50 legal substances that cause its kits to produce false positives for heroin, cocaine, or methamphetamines. “Court records show chocolate sometimes turns the liquid a similar shade of green as heroin,” according to ProPublica.

A Rolling Snowball of Errors

Prison Legal News and Criminal Legal News have reported extensively on the frequency with which encounters with police can turn deadly. Malcolm Gladwell’s 2019 book, “Talking to Strangers,” attributes this effect in large part to police training that teaches officers to treat others with intense suspicion, prompting a hostile response to otherwise seemingly innocuous statements or behavior.

With police primed to be suspicious, officers are less likely to believe that a powdery substance found during a DUI stop is innocuous. Beginning in the 1960s during the early years of the War on Drugs, companies developed the roadside testing kit to assist officers to identify such unknown substances.

“The tests are cheap – 2 apiece or less – and they are enormously convenient for police,” wrote Ryan Gabrielson for ProPublica in 2020. “Officers drop suspicious material in a pouch of chemicals and look for changes in color that might indicate the presence of illegal drugs.”

A positive result on a field test kit can lead to extremely negative outcomes, as this is enough to meet the probable cause standard required to arrest and detain a person on charges of drug possession or trafficking. For many years, in places like Las Vegas, possessing even a small amount of a substance could result in a steep bail amount and a lengthy stay in county jail.

Though proper lab tests are far more reliable and can sort innocuous substances from narcotics, prosecutors “routinely resist efforts to have drug evidence retested in the lab, often keeping those who fight charges in jail longer.”

Prosecutors for years also made presentations to judges vouching for the reliability of the kits, which predisposed judges to accept their results as authoritative. But we now know better.

“If you’re wondering why the public defender is pleading these cases, it’s because the alternative is horrific,” said Phil Kohn, chief of the Las Vegas Public Defender’s Office, acknowledging that lengthy stays in county jail have the effect of coercing even innocent defendants into accepting a plea deal.

In 2015, the Las Vegas PD made around 5,000 arrests for drug offenses, resulting in 4,600 convictions, with “nearly three-quarters of them relying on field test results, according to an analysis of court data.” Further, the vast majority of these cases do not involve confirmation by a lab test. According to Gabrielson, drug “arrest and lab testing data show the number could be as low as 10 percent.” And, at least in 2015, the department’s policy was to destroy evidence samples after a plea deal was entered in court, making exonerations impossible without the blessing of prosecutors.

The reason Houston was able to exonerate so many people at once hinged on one major difference between Houston and Las Vegas: Houston retained their evidence samples even after the case was ostensibly closed. Subsequent lab tests revealed the substances in these cases were innocuous.

Big Statistics

There are thousands of policing jurisdictions ranging from small town police to departments with a small army of officers in places like New York City or Los Angeles, and many jurisdictions overlap (county sheriffs and city police patrolling the same area with both conducting traffic stops). In 2011, when the Department of Justice hired a research firm to conduct a national survey, it found that every jurisdiction contacted was using some brand of field test kits. This is, of course, big business for companies like the Safariland Group that make these kits.

“The roadside drug testing devices market in the U.S. was valued at $298.9 [million] in 2021” and is expected to reach $498.8 million by 2031. This number also includes alcohol testing using breathalyzers, “accounting for around 62% share” of the market. By inference, this means field test kits represent $113 million in annual spending by police.

The law enforcement response, however unjust, is intended to address a serious problem in the US. The National Institute of Drug Abuse (“NIDA”), one of the National Institutes of Health, collects and publishes statistics on drug use and abuse in the country.

According to NIDA, around 52 million people have used prescription drugs for non-medical reasons at least once in their lifetime, with Vicodin and OxyContin being the most abused prescription drugs among young people.

NIDA’s 2021 National Survey on Drug Use and Health revealed that around 11.7 million people aged 16 years or older drove under the influence of selected illicit drugs, including marijuana. Men are more likely than women to drive under the influence of drugs or alcohol, and the largest age segment who drive after taking drugs is adults between 21 and 25.

Car crashes are the leading cause of death among young people aged 16 to 19 years, and drug use is commonly linked to car crashes. In 2016, 19.7 percent of drivers who drove under the influence tested positive for some type of opioid. Further the “vehicle crash risk associated with marijuana in combination with alcohol, cocaine, or benzodiazepines appears to be greater than that for each drug by itself.” According to the Governors Highway Safety Association, “43.6 percent of fatally injured drivers in 2016 tested positive for drugs and half of those drivers were positive for two or more drugs.”

Behind the statistics are thousands of ruined lives every year, and our society should be taking reasonable steps to address such public health concerns. But using tests with such a high rate of error and subsequently destroying more lives is not the answer.

Unaccountable Harms

The use of field test kits by police departments could be improved by raising awareness of police and administrators of courts to improve the process. In this way, police and courts are accountable to the communities they serve. Presently, administrators are not accountable to prisoners and rarely are communities sufficiently aware of what happens behind prison walls to force the kinds of change necessary to affect the measure of accountability. Further, prison guards see themselves as law enforcement and use many of the same strategies to surveil oppressed prison populations that police
use in communities.

Drugs are as much of a problem in prison as they are in the streets of the poorest communities, possibly because prisons house individuals with higher incidences of poverty and mental health problems.

The prison staff from all over are constantly being convicted of distributing contraband, including narcotics, inside prisons, administrators tend to instead focus on visitation and prisoner mail when hunting for drugs.

How this issue intersects with field test kits is difficult to thoroughly illuminate because of the (intentionally) opaque nature of prisons, but court cases in two states can shine some light on the larger problem.

California Department of Corrections guards were using the kits to test crumbs and shreds of paper, and then, charges were filed when the kits tested positive for heroin and methamphetamine. After several such defendants refused to plead guilty and subsequent lab tests established their innocence, public defenders filed a suit challenging the validity of these kits to support an indictment.

Ruling in early 2018, Judge Christopher Plourd of the Imperial County courthouse in California ruled that the NIK public safety brand test kits made by Safariland Group did “not meet a scientific admissibility standard” and therefore could “not support the grand jury indictment.”

A Massachusetts case ended similarly after MDOC prisoners filed a class action suit. In October 2021, Suffolk County Superior Court Judge Brian Davis granted a temporary restraining order preventing prison officials from using the kits to test incoming mail, including legal mail. His ruling referred to the NARK II brand kits used in MDOC prisons as “arbitrary and unlawful guesswork.” Evidence produced as part of the hearing revealed that subsequent lab tests found 38% of the samples retested did not contain the alleged drug.

“For years, these tests have had this unjustified scientific veneer,” said Des Walsh, founder of the Roadside Drug Test Innocence Alliance. “Finally, we believe the tide is turning with this dawning awareness of the unacceptably high rate of false positives.”

“The net effect of DOC’s continuing use of the NARK II Test,” wrote Judge Davis, “is to both subject a significant number of incarcerated persons to unwarranted punishment, and to broadly chill and inhibit the rights and ability of all incarcerated person within DOC facilities to meaningfully
participate in their own legal defense.”

During a hearing on the California case, guards were called to testify about their use of the kits in prison. One guard, David Eustaquio, testified that he had used the kits more than 200 times during his career, yet had no idea about the kits’ accuracy.

“He said he’d never had to explain the results beyond saying the color change meant the test was positive for an illegal drug,” explained ProPublica.

Even when they weren’t referred for additional prosecution, prisoners were subjected to solitary confinement or denied parole eligibility on the basis of these kits, delaying their reentry to communities and harming the relationships with family members. And there is no way of knowing how widespread this problem is without voluntary disclosure from prison officials about the continued use of these kits.


Field test kits are not a good method for detecting illegal substances, but they satisfy the desire for law enforcement to make an on-the-spot determination about whether someone possesses narcotics. This desire sprang from the War on Drugs, which is widely acknowledged to have been a failed endeavor.

However, we now understand that these kits are not accurate and should no longer be used to detain, prosecute, or punish anyone without a confirmatory lab test.

“It’s sloppy work,” said David LeBahn, president of the Washington-based Association of Prosecuting Attorneys. “If they haven’t heard about Houston, people better start paying attention.”

Citizens concerned about the use of field test kits are encouraged to speak to their local prosecutors, who are elected or appointed officials, and make sure they are aware of the liability regarding the continued use of field test kits.

For the purpose of detecting and interrupting drug trafficking, a lab test is going to be more valuable. It allows officers to direct their attention towards persons who actually possess narcotics, even if that attention is somewhat delayed. When officers don’t waste resources hounding and housing innocent people, those resources can be better spent elsewhere.

Regarding the issue of drugged driving, oral fluid test kits – which use a laser to detect drugs or their byproducts in saliva – are more reliable than, and as portable as, a breathalyzer. These can detect drugged drivers without having to test random substances found in a person’s vehicle.

It is long past time when these test kits should have been retired from widespread use. Any legitimate law enforcement purpose is better served by using tests that are accurate, instead of relics designed decades ago to prosecute the War on Drugs. As with every war, there are far too many innocent casualties of war, and in this case, the
perpetrators are field test kits.




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