THE PROBLEM
Each year, according to the field drug test study released in December 2023 by the Quattrone Center at the University of Pennsylvania Carey Law School, more than 750,000 people are arrested based on field drug tests known to produce false positives. Although the study found that the true nationwide error rate of field drug tests could not be determined, it estimated that approximately 30,000 people are arrested each year after being falsely implicated by a presumptive color-based test.
The study also noted that false-positive rates ranging from 15% to as high as 38% have been observed, and concluded that field drug tests are likely the largest contributing factor to wrongful arrests and convictions in the United States.
https://www.law.upenn.edu/institutes/quattronecenter/reports/field-drug-test-study/
The damaging impact of these error-prone tests had previously been identified on a local basis in Harris County, Texas, where 94 of 140 drug-possession exonerations in 2016 and 2017 resulted from prosecutions involving roadside or field tests that inaccurately identified illegal substances.
http://www.law.umich.edu/special/exoneration/Documents/Drug_Cases_2016.pdf
Concerns about the reliability of roadside drug tests are not new. In 1974, the Commerce Department’s National Bureau of Standards stated that roadside drug tests “should not be used as sole evidence for the identification of a narcotic or drug of abuse.” In 1978, the Department of Justice determined that “field tests should not be used for evidential purposes.”
Because of their known inaccuracy, these $2 roadside/field drug tests are inadmissible at trial in virtually all jurisdictions. Instead, prosecutors must present laboratory test results as evidence of narcotic identification in court.
However, more than 90% of drug possession cases never go to trial. For many defendants who cannot afford bail, remaining in jail for weeks or months while awaiting laboratory confirmation can result in the loss of employment, housing, and in extreme cases the removal of children into the foster system. As a result, many defendants accept plea deals that leave them burdened with a drug-possession conviction.
In many instances, these defendants are entirely innocent, yet their lives are derailed by a roadside drug test known to produce inaccurate results. This represents a needless tragedy for those individuals, their families, and their communities. It undermines faith in law enforcement agencies and the important work they do every day, and it imposes significant costs on the criminal justice system and taxpayers through unnecessary prosecutions and incarceration.
The harm caused by inaccurate roadside drug tests disproportionately impacts minorities in general, and African Americans in particular. Numerous studies have shown that Black drivers are stopped more frequently than White drivers relative to their share of the driving-age population, and that after a traffic stop, Black drivers and their vehicles are more likely to be searched.
This disparity becomes particularly corrosive when combined witha flawed drug test known to produce false positives. The Quattrone Center study found that Black people experience erroneous drug arrests resulting from inaccurate field drug tests at a rate three times higher than their White counterparts.
See the Fox 13, Tampa Bay, Florida investigation showing how roadside/field drug tests falsely identify common household items as illegal drugs.
Read Pro Publlca’s report by Ryan Gabrielson and Topher Sanders in the New York Times magazine.
"How a $2 Roadside Drug Test Sends Innocent People to Jail".
THE SOLUTION
There are simple, practical ways to minimize the tragic impact of inaccurate colorimetric field drug tests:
Stop using field drug tests as a basis for arrest and detention. In simple drug possession cases, jurisdictions should adopt a cite-and-release policy pending confirmation from an accurate laboratory test.
Provide funding for law enforcement to convert to portable electronic field test devices that use technologies such as mass spectrometry or Raman spectroscopy. Although these devices are not as accurate as full laboratory equipment, their ability to determine thechemical structure of unknown substances makes them significantly less likely to generate false positives.
If roadside or field drug tests continue to be used as a basis for arrest and prosecution, no charge for simple drug possession should be entered without a laboratory test confirming the presence of a controlled substance. If an individual wishes to enter a plea agreement in any case in which a field drug test is used, they should be advised that field drug tests are known to give false positives, and that they have a right to laboratory testing.
In 2018, the Forensic Technology Center within the National Institute of Justice (NIJ) stated that “color-based tests are not always accurate” and published a comprehensive study evaluating more reliable portable electronic field-testing devices. In its conclusion, the NIJ reported that these devices “offered significant advantages over traditional color-based testing, including comprehensive one-step testing, objectivity, specificity, safety, chain-of-custody corroboration, technical support, and versatility.”
Providing more accurate electronic test devices to law enforcement agencies and the adoption of cite and release in simple drug possession cases would support better law enforcement, deliver justice for thousands of innocent people each year and conserve millions of dollars and other public resources currently spent on arresting and prosecuting drug possession cases based on error-prone field drug tests.
WHAT WE’RE DOING
A challenge in seeking reform in this area has been obtaining comprehensive data on the extent of the use and impact of roadside/field drug tests. To address this information gap, we commissioned an independent national study by the University of Pennsylvania’s Quattrone Center for the Fair Administration of Justice. Released in December 2023, the study exposed the tragic impact of these inaccurate tests. https://www.law.upenn.edu/institutes/quattronecenter/reports/field-drug-test-study/
We are actively working with innocence organizations and other criminal justice groups on state legislation and related initiatives to reduce the harm caused by field drug tests. One example is Colorado House Bill 26-1020, which passed unanimously with bipartisan support in both the Colorado House and Senate. The bill was based on recommendations from a working group of legislators, law enforcement officers, prosecutors, defense attorneys, and other experts convened to address concerns about inaccurate field test results.
Under this legislation, when a colorimetric field drug testis used and a person is suspected solely of misdemeanor drug possession, an officer must issue a summons rather than detain the individual. This provision ensures that no one is subjected to the coercive effects of pretrial detention on a misdemeanor drug possession charge while awaiting confirmation from a laboratory test. In addition, if a person seeks to enter a plea for drug possession, the trial court must first provide an advisement stating that colorimetric field test kits have known error rates and that the defendant has the right to plead not guilty and request testing by an accredited laboratory.
In addition to supporting legislation and other policy initiatives, we serve as an information resource for criminal defense attorneys and for individuals facing prosecution or pursuing civil litigation arising from inaccurate field drug tests. For example, in April 2025 we filed the following amicus brief in support of a carceral appellate case before the Ninth Circuit Court of Appeals: https://rdtinnocencealliance.org/s/ECF-017-Brief-for-Roadside-Drug-Test-Innocence-Alliance-as-Amicus-Curiae-in-Support-of-Appellant2051.pdf