The medical use of cannabis is legal, with a doctor’s recommendation, in 36 states. The recreational use of cannabis is legal in 16 states, with more considering legislation. There is little known about the number of people who are taking advantage of this sea change in the law—many speculate that the number of people “using” marijuana hasn’t changed a whole lot.

What many—especially those in public safety such as police, EMS, and fire—can state with certainty, however, is that vehicle collisions where marijuana intoxication was a factor have increased substantially in recent years. 

Stoned Driving Statistics

In 2016, the National Highway Traffic Safety Administration (NHTSA) Fatality Analysis Reporting System (FARS) found that drugs were present in 43.6% of fatally injured drivers with a known drug test result. Cannabis was the most commonly found drug in the systems of drug-positive fatally injured drivers with more than 41% of them testing positive for some form of cannabis.

A host of public and private sector organizations require that employees be “sober” while on the job. But in the current environment of legal weed existing drug testing methods have become inadequate. Consequently, an emergent industry has grown up to provide rapid cannabis testing that can be used by employers and by law enforcement. One of the greatest needs is a reliable tool that law enforcement can use to address the problem of detecting impairment on the roads due to marijuana use.

A Growing Problem

One of the leading companies working on developing accurate and rapid drug testing technologies for use by law enforcement is Abbott Laboratories. The company produces the SoToxa Mobile Test System.

“Unfortunately, the true magnitude of the drug-impaired driving problem is not known due to a lack of drug testing,” says Erin Holmes, director of global road safety for Abbott. “While states do a good job of testing fatally and seriously injured drivers for the presence of alcohol, drug testing rates are far lower. Despite there being limitations in the fatality data, a variety of studies are painting a picture that shows drug-impaired driving is increasing. What’s true is that thousands of innocent lives are lost every year to this entirely preventable behavior.”

There are several different sources that can be consulted for statistics on the impact of marijuana usage on highway safety. They include fatality and injury data, roadside surveys, and studies examining drug-impaired driving in states that have legalized recreational cannabis. While there are recognized limitations in fatality data, one consistent finding is that cannabis is the most commonly detected drug—aside from alcohol—in the systems of fatally injured drivers and drivers involved in fatal crashes.

Holmes explains, “It is common for cannabis to be used in combination with other substances, which can produce significantly greater impairment and increase crash risk. Cannabis-impaired driving, in particular, is a problem that warrants immediate action.”

NHTSA’s National Roadside Survey (NRS) measures the extent of drug-impaired driving in this country. The most recent NRS was conducted in 2013-2014, and found that 22.5% of weekend nighttime drivers tested positive for illegal, prescription, or over-the-counter medications with 12.6% of these drivers testing positive for Delta-9 tetrahydrocannabinol or THC (the main psychoactive ingredient in cannabis). Comparing results between the 2007 and 2014 NRS, it was found that the percentage of drivers testing positive for THC increased by 48% over that seven-year span (from 8.6% to 12.6%).

Holmes notes further that CDC data found that in 2018, approximately 12 million people aged 16 and older reported driving under the influence of cannabis in the past year. That bears repeating because it is clear evidence of the need for stoned driving detection technology. Approximately 12 million people ages 16 and older reported driving under the influence of cannabis in the past year.

Holmes says the state with the most robust drug-impaired driving data is Washington.

“Following the legalization of recreational cannabis in 2012, numerous studies have been conducted to determine whether this policy decision led to an increase in cannabis-impaired driving. The Washington Traffic Safety Commission (WTSC), AAA Foundation for Traffic Safety, Pacific Institute for Research and Evaluation (PIRE), and others have conducted analyses examining the prevalence of cannabis-impaired driving and trends over time,” she says.

According to data collected by Abbott over the ensuing years, the AAA Foundation for Traffic Safety has conducted several studies in Washington to determine whether cannabis-impaired driving increased following the legalization of recreational cannabis. A study released in 2020 found that the percentage of drivers involved in fatal crashes who tested positive for cannabis doubled since the state legalized the drug for recreational use. The percentage of drivers who tested positive for THC increased from about 9% in the five-year period before legalization to approximately 18% in the five years afterward. Roughly 1 in 5 drivers involved in fatal crashes in 2017 tested positive for THC.

“This data is merely a snapshot, but it demonstrates that drug-impaired driving is a significant problem,” Holmes says. “Cannabis-impaired driving, in particular, is a common and increasing behavior as is the incidence and seriousness of polysubstance-impaired driving which often involves THC and alcohol.”

Cannabis Detection

SoToxa from Abbott Laboratories can detect the presence of THC in the oral fluid of a user. This can determine if a driver has smoked or vaped a cannabis product recently enough to be impaired. Methods used to determine alcohol impairment do not work for cannabis because THC remains in the bloodstream much longer than alcohol.

Abbott developed SoToxa to address the growing public health and safety concern of drug-impaired driving, Holmes says. “No roadside drug test can claim to be 100% accurate, which is why we recommend confirmatory lab testing before a conviction is secured. However, SoToxa is the most advanced and reliable testing-tool available to law enforcement today. Knowing that SoToxa provides reliable and highly accurate results gives police and policymakers the confidence they need to make decisions in the interest of public safety.”

According to Abbot—and they obviously have a vested interest in making such a statement—SoToxa is “the most accurate, reliable, and practical on-site drug screening method available for roadside use.”

The technology is portable, lightweight, and fits within the palm of an officers hand which makes it ideal for use in the field.

“As officer safety is an important consideration, SoToxa is designed to be easy to use and the collection of the oral fluid (saliva) sample is done by the suspect to maintain a safe distance,” the company says in written documents.

A collection device includes a simple saliva swab that allows for the collection of the oral fluid in less than a minute. Once the sample is obtained, the officer inserts it into a cartridge and the portable analyzer. In under five minutes, the analyzer interprets and determines the test outcomes, which eliminates the subjectivity of visually interpreted results. SoToxa will alert the officer if the driver is positive or negative for six common drug classes—amphetamines, benzodiazepines, cannabis, cocaine, methamphetamine, and opiates.”

Numerous law enforcement agencies are currently using SoToxa to enhance impaired driving investigations and identify drivers under the influence of drugs.

Abbott says that SoToxa is very different from a blood or hair test for drug usages. It’s much more immediate, so it only measures the presence of active drugs in order to protect public safety and aid law enforcement officers following the legalization of cannabis for recreational use. “An incredibly important distinction is that SoToxa measures only the active presence of drugs. This means that the window of detection is short and only drugs that have been used within the last few hours will produce a positive result,” Holmes says. “For example, if cannabis is smoked or vaped, the drug will be present within minutes in the oral fluid. SoToxa would simply measure the presence of THC based on a cutoff level. A common concern related to cannabis use is that the drug can be detected in the body for days and sometimes weeks after consumption. With oral fluid screening, this is not an issue as SoToxa only tests for active THC as opposed to inactive metabolites.”

Holmes adds that SoToxa is part of Abbott’s mission to improve public safety. “At Abbott, we believe in the freedom to get behind the wheel without the fear of impaired drivers and the poor judgements they make,” she says. “This is why Abbott is creating the tools to keep us safe and secure, no matter what changes in drug policies and decimalization come down the road.”   

Doug Wyllie is contributing web editor for POLICE.