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5 Factors That Can Invalidate a Field Sobriety Test

 Posted on September 27, 2022 in DUI

dupage county dui defense lawyerOne of the first attempts made by an officer to discern whether a detainee at a traffic stop is under the influence is often field sobriety testing. Field sobriety tests are used to measure an individual’s level of impairment, and to build evidence to be submitted to a court of law following an arrest for DUI. Yet, the methods used in field sobriety testing are imperfect and frequently, the results are influenced by environmental, medical, or other factors that may negate the test’s effectiveness. The imperfections in these testing techniques lie in the fact that these tests are typically administered outdoors, in whatever location the detainee has stopped their vehicle after observing an officer’s order to pull over. A skilled attorney may be able to argue that the results of a field sobriety test have been influenced by factors other than intoxication and effectively null their worth as evidence in a DUI case. 

Environmental Factors Having an Impact on the Results of Field Sobriety Testing

Environmental factors influence the effectiveness of field sobriety testing by creating additional difficulties in performing these tests due to the location in which they are given. Environmental factors can include: 

  • Uneven surface - Balancing on an uneven surface can cause a sober person to falter in their step. 

  • Mud or rain - When a person’s feet sink slightly into the ground with each step due to the concentration of water in the upper ground, the force needed to lift each foot may be sufficient to throw a person off balance or force them to utilize their upper appendages to retain balance. 

  • High winds - High natural winds may exert forces on a person’s body causing them to lean or tilt when otherwise they would have experienced no significant difficulty remaining upright. Further, it may be more challenging to understand an officer’s verbal instructions in such conditions.

Personal or Medical Factors Influencing Ability to Perform Field Sobriety Testing

Factors other than alcohol or drug intoxication potentially influencing the results of a field sobriety test may include: 

  • Balance impairing disorders - Inner ear infections, natural vertigo, an expressed gene for flat feet, dysautonomia, or other medical conditions having a noticeable effect on a person’s balance may suggest a cause other than impairment for a person’s inability to pass field sobriety testing. 

  • Improper footwear - Wearing high heels can create undue difficulty in balancing body weight on one foot or in a straight line, as such footwear is notorious for causing uneven gait. Likewise, bare feet may alter a person’s gait should they land upon a pebble or other uncomfortable debris. 

If such circumstances were present at the time of your field sobriety test, your attorney may have grounds to argue that your inability to pass was caused by a factor other than intoxication. 

Call a DuPage County Criminal Defense Lawyer

Davi Law Group, LLC utilizes a variety of legal strategies to defend those accused of intoxicated driving. Our knowledgeable Wheaton DUI attorneys will explore any possible avenue of defense in order to guard against an avoidable conviction. Call 630-580-6373 for a free consultation. 



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