If a driver is pulled over in Colorado and police suspect he or she is impaired, the officer will request the individual to perform some tests by the roadside to determine if the operator is drunk or high. The tests, called standardized field sobriety tests (SFSTs) or roadside tests are used by police to determine if there is probable cause to arrest the driver for driving under the influence (DUI) or driving while ability impaired (DWAI).
The test is comprised of three components:
-
- horizontal gaze nystagmus (HGN);
- walk and turn; and
- one leg stand.
The standards for performing these tests are determined by the National Highway Traffic Safety Administration (NHTSA), the Colorado Department of Transportation (CDOT) and the Colorado Peace Officers Standards and Training (POST) agency.[i]
Horizontal gaze nystagmus is an eye test where the officer has a subject track an object (such as a finger or a pen) to the left and right sides. Police are looking for involuntary jerking of the eyeballs (nystagmus), which can be a sign of alcohol intoxication or impairment from certain drugs.
A walk and turn test is classified as a “divided attention test.” This type of exam requires the subject to concentrate on both mental and physical tasks at the same moment.[ii] In a walk and turn test, the driver will be required to walk a straight line for a designated number of steps in a specified manner, turn around and follow the same path back to the starting point.
A one leg stand is also a divided attention test.[iii] Here, the test subject will raise either foot six inches off the ground, stand on one foot, and audibly count to thirty (30) seconds.[iv]
While the tests are not completely accurate, they do detect impairment to some measurable degree. According to the NHTSA, studies have shown the nystagmus test was 88% accurate, the walk and turn was 79% accurate, and the one leg stand was 83% accurate in identifying subjects whose blood alcohol content (BAC) were 0.08 or more.[v]
Does a driver in Colorado have to complete the SFSTs? The short answer is “no” – a driver does not have to complete roadside testing if requested by an officer. However, there are ramifications for refusing to complete them. Colorado law permits the refusal to be admitted as evidence at trial by the prosecution.[vi]
There are also many methods for attacking the accuracy of the actual tests performed. For example, a test subject’s weight (i.e. – obesity) or mobility issues like arthritis and joint replacements can affect how one performs the walk and turn or one leg stand tests. Illness and exhaustion can impact horizontal gaze nystagmus. If the driver has a medical condition, such as diabetes, this can impact how he or she appears to a police officer and mimic impaired driving. The officer’s training and (in)experience at SFSTs can also affect the exam’s results.
In summary, while failing roadside testing is a complication for a defendant, it is not definitive evidence of impaired driving. Avenues exist to attack the evidence and possibly exclude its use at any trial for DUI or DWAI.
If you’ve been charged with DUI or DWAI, contact us to learn how we can challenge the roadside testing in your case.
[i] See “SFST DWI Detection and Standardized Field Sobriety Testing” published by NHTSA revised 2/2023 (accessed at: https://www.nhtsa.gov/sites/nhtsa.gov/files/2023-03/15911-SFST_Participant_Manual_2023-tag.pdf); and “Standards for the Standardized Field Sobriety Testing (SFST) Program” published by CDOT and POST on 10/01/2015 (accessed at: https://www.codot.gov/safety/impaired-driving/assets/documents/Field_Sobriety_test_standards.pdf).
[ii] “SFST DWI Detection and Standardized Field Sobriety Testing,” p. 12.
[iii] Id.
[iv] “SFST DWI Detection and Standardized Field Sobriety Testing,” p. 16.
[v] Id. at p. 31.
[vi] § 42-4-1301(6)(d), C.R.S.; McGuire v. People, 749 P.2d 960, 962-63 (Colo. 1988).
