The many problems of roadside drug screening

Earlier this year, the Federal Government invited 24 police officers across Canada to test a pair of devices that claim to screen drug-impaired drivers. The roadside drug screening evaluations were conducted between December 18, 2016 and March 6, 2017 and included several officers from the Vancouver Police Department.

Two devices were selected for the pilot test: the Securetec DrugRead and the Alere DDS-2. Both of these devices had been previously tested for reliability with positive results. As a result, Public Safety Canada determined both the devices were reliable and set about using them on the road.

Positive readings were more likely to occur when the device was operated in temperatures colder than what the manufacturer suggests.

But “reliable” is not a word that you could attach to these devices based on this evaluation.

Um, oh boy, the problems they encountered… But you wouldn’t know it from reading their press release which quotes Public Safety Minister Ralph Goodale saying “this technology works,” and that it would give police more tools to detect drug-impaired driving.

How the drug-impairment screening devices work

Both the devices have two main components: swabs intended to be placed in the mouth of the person being tested, and a machine that the swabs plug into for drug analysis. Both devices are advertised as being capable of detecting cannabis, opiates, cocaine, amphetamine, methamphetamines and benzodiazepines.

For the Securetec DrugRead, the operator’s manual suggests an officer must first split the swab into two pieces, the sample collector and a “test cassette.” The person being tested should then “run their tongue around the inside of their mouth in a circular motion three times” before the sample-collecting “DrugWipe” swab is wiped on the tongue or the inside of the cheek. When enough saliva has been collected, the swab changes colour. The swab is then reconnected with the “test cassette,” and the whole thing is placed into the screening device. The officer then presses down on the test cassette until a capsule breaks. The DrugRead screening device can then measure for the presence of drugs, a process that can take as long as eight minutes. Results will show up on the screening device’s built-in display.

The Alere DDS2 follows a similar procedure. The officer first removes a test cartridge from its packaging and inserts the cartridge into the DDS-2 screening device. The device then confirms whether cartridge is valid, and if so, the officer can then collect a saliva sample. The collection swab is then taken out of its own packaging, and must be actively swabbed “around the gums, tongue and inside the cheek” of a subject until it changes colour. The swab is then placed into the screening device, through the attached cartridge, and analysis begins. Results are available in about five minutes, and will show up on the device’s built-in display. (Note: the manufacturer rebranded the Alere DDS2, now calling it the Abbott SoToxa (sometimes spelled Abbot) and it was approved for use in Canada as of June 24, 2019.)

Many issues identified when testing the drug impairment screening devices

Accompanying the press release on Tuesday was the report prepared by the Policy and Development Serious and Organized Crime Strategies Division. This report identified some serious issues with both the Securetec and Alere devices. Officers raised concerns that both devices require police to spend nearly 10 minutes collecting samples and obtaining results. The results themselves also suggested that positive readings were more likely to occur when the device was operated in temperatures colder than what the manufacturer suggests. This happened a lot.

The Securetec DrugRead machines themselves are suggested to operate between 5° C to 40° C, while the sample collector and test cassette cartridges it uses are suggested to operate between 5° C to 25° C. The Alere DDS-2 machines have better tolerances, and were able to go down to -20° C and up to 45° C. The cartridges that go with the Alere device, however, were much worse, with the manufacturer suggesting they operate between 15° C and 25° C. Along with Public Safety Canada’s test results, this suggests both devices may have difficulty producing accurate readings during colder times of the year in much of Canada.

The devices are also supposed to indicate a “temperature malfunction” when they’re used outside the suggested operating temperature. Though officers used the devices outside the temperature range 731 times, the devices only reported temperature malfunctions 14 times.

Public Safety Canada had this to say in its report:

“Proportionally, tests conducted outside of suggested operating temperatures were more likely to produce drug-positive results (i.e., while 64% of all tests occurred outside of suggested operating temperatures, 80% of all positive results were produced outside the suggested range). At present, it is unknown whether this finding is attributable to technical or procedural issues, for example whether the devices are more likely to show positive results when tested in extreme cold temperatures.”

The drug impairment screening devices have a 7% malfunction rate

Seven times out of 100, the tests just won’t work. Officers listed the reasons as due to temperature, power or battery, weather, or unknown reasons. Sometimes, the devices just powered off during analysis (much like roadside breathalyzers). Three of the devices, two Alere and one Securetec, only produced positive drug readings. The report does not say how many devices were tested in total from the two manufacturers.

Both manufacturers also suggest the devices must be kept still during analysis. Officers reported that 6% of the malfunctions were due to the device being tilted during the lengthy analysis time.

Other issues that may be a cause of concern

Officers who used the machines were concerned that both machines took a while to collect samples, analyze and produce results. Particularly for the Alere DDS-2, the act of swabbing a driver’s mouth could take up to two minutes to ensure enough saliva is collected. Imagine an officer standing there, with a swab in your mouth for two minutes just so the screening device will work. It was such a hassle that officers preferred to have the drivers being tested hold the swab themselves, which potentially raises issues of whether the officer had full control of the device during the whole screening process. In another sticky point of concern, the Alere mouth swabs can leak a “buffer fluid” when being used in someone’s mouth. The manufacturer “has since stated that this fluid creates no health concerns and will be assessed.” OMG!

The Securetec DrugRead is not without issues, either. Officers didn’t like how they needed both hands to use the Securetec device. They also didn’t like the eight minutes it took for an analysis to be made while in close proximity with the person tested, suggesting that this could “put officers in a vulnerable position.”

Previous research tested the reliability of these devices

As proof of reliability, Public Safety Canada relied on an assessment published in the Canadian Society of Forensic Research Journal published in December. In the assessment, researchers compared results from three models of drug screening devices to results of oral samples sent to the lab. While three models were tested, two of them ended up being the ones used in the Public Safety Canada pilot test: the Securetec DrugWipe 6S (which connects to the DrugRead) and Alere DDS-2.

The testing confirmed that the screening devices were quite accurate when it came to measuring for the presence of cannabis, cocaine, opiates, and to a lesser extent, methamphetamines. But the screening devices struggled to consistently detect the presence of amphetamines and benzodiazepines.

For reference, here are the results for sensitivity (hit rates, or ability to confirm drug use):

Opiates – 90%

THC – 87%

Cocaine – 85%

Methamphetamines – 81%

Amphetamine – 77%

Benzodiazepines – 59%

And the results for “false” positives:

Opiates – 6.9%

THC – 4.5%

Cocaine – 0.7%

Methamphetamines – 3.5%

Amphetamine – 3.6%

Benzodiazepines – 2.4%

Does this mean an officer can ask me for a saliva sample?

So far there is no section of the Criminal Code that authorized these types of tests for screening purposes. The closest relevant section of the Criminal Code is section 254(3.1). This section states that an officer who has reasonable grounds to believe someone is impaired by drugs or alcohol, and had recent control of a vehicle, can require an evaluation to determine whether there was in fact impairment. This is after the “screening phase” of an investigation, at which point the officer claims to have reasonable and probable grounds or “probable cause,” as they say in the USA.

The idea here is that to elevate their evidence to reasonable and probable grounds the police will soon be able to rely on the results of roadside drug screening. Currently there are no “approved” roadside drug screening devices. As for devices being considered, the Securetec and Alere devices only indicate a recent presence of drugs in a person’s system, and do not measure a person’s actual level of impairment.

Although it’s coming, it’s unclear when Immediate Roadside Prohibitions for drug impairment will be introduced. For drugs like marijuana, Governments have not established the level of THC required to be in a person’s body to consider them impaired and this may be impossible in any event. Even high concentrations of THC in a person’s system may not necessarily mean they’re impaired, especially if the person is a heavy, regular user of marijuana. We still have not seen research that can establish a link between levels of THC inside someone’s body and the likelihood of them causing a collision. Until then, the results from any device that claims to measure a driver’s impairment by marijuana are questionable, at best.