Investigating the feasibility of using an innovative new alcohol impairment testing device based on Drug Recognition Experts’ protocol

Author(s): Nachim, Roshan, Daneshi, North

Slidedeck Presentation:

Cannsight CARSP -Final



CannSight’s impairment detection technology simulates testing protocols used by Drug Recognition Experts (DRE) in law enforcement across the globe. DRE assessments are the current gold standard for drug and alcohol impairment detection. The DRE protocol was developed by The International Drug Evaluation and Classification (DEC) Program and the International Association of Chiefs of Police (IACP) with support from the US National Highway Traffic Safety Administration (NHTSA).


CannSight successfully completed its first IRB-approved clinical trial in Toronto, ON in Dec 2019. The purpose of the trial was to investigate the ability of CannSight Work 1.0 to accurately and reliably simulate the DRE testing process.


Twelve subjects (6 male and 6 female), between the ages of 21 and 55, participated in the study.

  • Subjects were divided in two groups: The alcohol group and the cannabis group. The subjects in the cannabis group self reported that they had consumed cannabis 6 times or more during the past year. 66.6% described themselves daily users.
  • All subjects were asked to abstain from using alcohol, cannabis and other recreational drugs for 24 hours prior to the testing session.
  • Cannabis subjects were tested using an approved oral fluid swab test (Dreger DrugTest® 5000) and alcohol subjects via a breathalyser before starting any testing procedure to rule out the presence of other substances that might confound results.
  • Subjects were asked to drink alcohol / smoke cannabis to achieve the target levels for body alcohol level (BAC > 8-10 mg/100ml) and THC concentration (> 5 ng/ml), respectively. Both these levels are above the legal per se limits for impaired driving in Canada and the USA.
  • A total of 48 impairment assessment tests were conducted under the supervision of a medical doctor (Medical Cannabis and Addiction Medicine specialists).
  • Each subject was tested four times for impairment as follows:
  • A baseline pre-alcohol/cannabis test by an in-person DRE
  • A post-alcohol/cannabis test by an in-person DRE
  • A baseline pre-alcohol/cannabis test by CannSight Work 1.0
  • A post-alcohol/cannabis test by CannSight Work 1.0
  • All test data was uploaded to our proprietary, AI-assisted, HIPAA / PHIPA-compliant Results Portal for “remote review” by a DRE, post-trial.


Following the consumption of alcohol or cannabis, all subjects achieved the target levels for body alcohol level (BAC > 8-10 mg/100ml) and THC concentration (> 5 ng/ml), respectively.

  • 83% of alcohol subjects were determined to be impaired following consumption of alcohol by both the in-person DRE and CannSight Work 1.0.
  • Cannabis subjects self-rated their impairment levels on a visual analog scale (VAS) within the range of 6/10 - 9/10 (0 = Not High, 10 = Very High) following consumption.
  • 33.3% of cannabis subjects were determined to be impaired by the in-person DRE and CannSight Work 1.0 after consuming cannabis (THC > 5 ng/ml).
  • More than 80% of subjects answered YES when asked if they would drive after they had achieved the target BAC and THC levels.


In line with current literature, our results confirm that there is NOT a linear correlation between THC levels in oral fluid and actual mental and psychomotor impairment levels, as seen by the 66.6% of cannabis users whose impairment determinations were negative.

  • Our results also confirm that “impaired behavior from acute use of cannabis differs between occasional users and long-term users. Chronic, frequent cannabis users exhibit less impairment in neurocognitive task performance from acute THC than do occasional users... (Phillips et al. 2015, D'Souza et al. 2008; Hart et al. 2001; Jones et al. 1981; Ramaekers et al. 2009)”.
  • Lastly, our results indicate that self-perceived levels of mental impairment do not correlate with actual impairment levels, as shown by differences in participant ratings of cannabis impairment on a VAS scale and the impairment determinations made by both DRE and CannSight Work 1.0 assessments.


  1. The results of this study show that CannSight Work 1.0 reliably and accurately simulates the official DRE testing protocol.
  2. Employers in safety-sensitive industries who are struggling to tackle the growing issue of worker impairment using traditional drug testing methods (i.e. urine and oral fluid), can leverage CannSight Work 1.0 to introduce the established scientific and legal framework of the official DRE testing methodology into their drug and alcohol testing programs.
  3. Police precincts in rural and remote communities who do not have physical access to trained DREs can gain virtual access to CannSight’s DRE consultants utilizing CannSight Work 1.0 and our Results Portal.
  4. A portable version or our technology leveraging our proprietary modified version of the official DRE testing protocol (currently under development) will speed up results-processing timelines and increase the scalability of our proprietary AI-assisted software. This technology will be invaluable to both roadside officers and employers with remote worksites.