Why the Workplace Impairment Test (the WIT) is based upon the DRE exam

Impairment is defined as “the state of being diminished, weakened or damaged especially mentally or physically” (Dictionary.com definition), or by being “in an imperfect or weakened state or condition” (Merriam-Webster Dictionary).  There is also legal case law (Regina vs STELLATO, 1994 SCC) which defines impairment as any degree of impairment from slight to great and not a marked departure from normal behaviour.

Safety sensitive positions, such as transportation, aviation, oil and gas and mining, and highly regulated activities such as driving are often examples that are used when discussing concerns pertaining to impairment in the workplace.  However, there are other types of work environments that can be considered safety-sensitive.  These include positions such as health care, compounding of medications, arranging loads of shipping materials, and crossing guards responsible for children getting to school safely.

Employees are the foundation of all companies. Ensuring all workplaces have the opportunity to be educated regarding alcohol and drug consumption and the effects of this consumption is essential.  It is incumbent upon the employer to ensure a safe workplace for everyone.

Validity of DRE Testing

The International Association of Chiefs of Police (IACP) with support from the National Highway Traffic Safety Administration (NHTSA) developed the Drug Recognition Expert (DRE) program in the early 1970s.  The training relies heavily upon the Standardized Field Sobriety Tests (SFSTs).

These psychophysical tests are the methods of investigating the mental and physical characteristics of a person suspected of alcohol or drug impairment. Most psychophysical tests employ the concept of divided attention to assess a suspect’s impairment.

Standardized Field Sobriety Testing is composed of three tests, Horizontal Gaze Nystagmus (HGN), Walk and Turn (WAT) and One Leg Stand (OLS). Developed from a series of controlled laboratory environments and assessed with field studies, scientifically validated clues of alcohol impairment have been identified for each of these three tests.

The validity and sensitivity of these tests have been demonstrated in three commonly referred studies, which include:




“To be genuinely useful, roadside tests must be valid and reliable; i.e., they must measure changes in performance associated with alcohol and they must do it consistently. To the extent that they meet the validity and reliability criteria, they can be expected to contribute to traffic safety by increasing the likelihood that alcohol-impaired drivers will be removed from the roadway by arrest. Importantly, they also will further serve the driving public’s interests by decreasing the likelihood that a driver who is not alcohol impaired will be mistakenly detained or arrested. Thus, the validity and reliability of the tests are important issues.

Overall, for 234 cases confirmed by breath or blood tests, officers’ decisions to arrest and release were 86% correct, and 93% of their arrest decisions were correct.”




“The results of decision analyses provide clear indication of SFST accuracy. Decision analyses found that officers' estimates of whether a motorist's BAC was above or below 0.08 or 0.04 percent were extremely accurate. Estimates at the 0.08 level were accurate in 91 percent of the cases, or as high as 94 percent if explanations for some of the false positives are accepted. Officers' estimates of whether a motorist's BAC was above 0.04 but under 0.08 were accurate in 94 percent of the decisions to arrest and in 80 percent of the relevant cases, overall.

The results of this study provide clear evidence of the validity of the Standardized Field Sobriety Test Battery to discriminate above or below 0.08 percent BAC. Further, study results strongly suggest that the SFSTs also accurately discriminate above or below 0.04 percent BAC.”



“The data obtained during this study demonstrate that 95% of the officers’ decisions to arrest drivers were correct decisions. Furthermore, 82% of their decisions to release drivers were correct. It is concluded that the SFSTs not only aid police officers in meeting their responsibility to remove alcohol-impaired drivers from the roadway, they also protect the rights of the unimpaired driver. These data validate the SFSTs as used in the State of Florida by Pinellas County Sheriff’s deputies who have been trained under NHTSA guidelines. SFST validity now has been demonstrated in Florida, California (1997) and Colorado (1995). There appears to be little basis for continuing legal challenge.”

Psychophysical Testing in the Workplace (the WIT)

Since 2008, police officers have had the authority to demand roadside SFST testing upon the interaction of a driver they suspect has alcohol or drugs in their system.  Up until now, this type of testing has not been readily available in the workplace. The Workplace Impairment Test (the WIT) allows your company the ability to test employees using the same standardized psychophysical testing used by police officers. This will help you to determine fitness for duty by ascertaining whether an employee is likely impaired.


By utilizing the same psychophysical test battery used in both the SFST and DRE testing, along with oral fluid or urine testing, employers will be able to utilize the most up to date and complete testing components for their employees to assist with maximizing safety in the workplace and long-term wellness for their employees.

Maintaining the standardized scoring and note taking by using the WIT app, employers are able to easily maintain their documentation and record keeping pertaining to any testing events, whether it is pre-access, post-incident, reasonable cause, follow-up or testing used in the assessment of an employee’s ability to work safely with their prescription medications or medically authorized cannabis.


These standardized, valid psychophysical tests will change the way your company makes determinations of fitness for duty. We are excited to offer this to you and look forward to speaking to you and your company about our innovative workplace testing solutions.