Can Bad Weather or Injuries Affect FST Results in North Carolina?

By Doug Edwards

  |  

DUI/DWI Defense

  |  

Last Modified on Oct 17, 2025

Field Sobriety Tests (FSTs) are used to determine whether someone is intoxicated while driving. They are conducted when a police officer pulls someone over on suspicion of driving while under the influence. However, these tests are not perfect. If you’ve ever wondered, “Can bad weather or injuries affect FST results in North Carolina?”, it is important to get clarity on the accuracy of these tests.

An Asheville DUI lawyer may be able to help if you have been wrongfully arrested due to poor FST results. Many factors can affect the results of an FST, including weather conditions and a driver’s prior injuries or medical issues. Officers must take these factors into account when conducting FSTs.

How Bad Weather Can Impact FSTs

Driving becomes more dangerous in the rain because the road becomes slippery and can possibly flood. Hydroplaning can also occur. In North Carolina during the winter, ice may appear on the road and can also make the road slippery. Accounting for bad weather begins with an officer’s observation of a driver’s performance during inclement weather.

If an FST is nevertheless administered, it is advised that a Walk and Turn FST must be administered on a dry, level, and non-slippery surface. If the surface becomes wet, uneven, or slippery due to weather conditions like ice, rain, or snow, the test results may be inaccurate. A driver might slip and fall while performing this test on this kind of surface.

Wind may also affect how a Horizontal Gaze Nystagmus test is taken. Wind in someone’s face may cause their eyes to close, and if dust gets into their eyes, they may not be able to see properly.

How Injuries Can Impact FSTs

There are many injuries or medical conditions that may affect the accuracy of an FST. Officers conducting an FST must ask the driver whether they have any physical issues or disabilities before beginning a test because they may not be able to complete it accurately due to their ailments.

With Horizontal Gaze Nystagmus tests, officers look at the eyes. Prior to conducting the test, officers must watch for unequal pupils and whether the eyes track the object together or not. These may be signs of an injury, a medical disorder, or blindness. Certain medications can also cause nystagmus.

According to SCRI studies, individuals with back, leg, or inner ear problems faced difficulty when performing a Walk and Turn test. These individuals, as well as those who are overweight by at least 50 pounds, had difficulty performing the One Leg Stand tests. Because of the physical nature of FSTs, it can be harder for people with prior injuries and disabilities to perform well, and that will affect the accuracy of these tests.

Hire a DUI Lawyer

If you are wrongfully arrested and charged with a DUI due to inaccurate field sobriety test results because of bad weather or injuries, take immediate legal action and hire a DUI lawyer. At Edwards Law, PLLC, we may be able to help. With our extensive knowledge and experience with DUI cases, we may be an asset in assisting your case. Contact our office today to get help.