The Problems with Walk and Turn Sobriety Tests

Posted by Doug Murphy | Dec 18, 2019 | 0 Comments

The walk and turn field sobriety test is a common trope in popular culture. Many television depictions of a DWI arrest involve some version of the accused “walking the straight line.” As one of the three standardized field sobriety tests, the walk and turn test is also commonplace in real-life DWI arrests. But should they be?

The most often-cited study regarding the accuracy of these tests suggests they are not a strong indicator of intoxication. According to the National Highway Transportation Safety Administration, this test only accurately identifies drivers with a blood alcohol concentration of .10 or more 68 percent of the time. While a 32 percent false-positive rate is very high, the figures buried in the study are worse. The overall accuracy rate was bolstered by the officer's ability to identify subjects that were highly intoxicated. This was not the case for the sober drivers in the study. The officers taking part reported that 52 percent of subjects under the legal limit failed the walk and turn test. This means even under the most favorable results, the majority of sober drivers showed false-positive signs of intoxication. 

The problem with the walk and turn test is three-fold. First, the results of this test are subjective and open to interpretation. Second, there are valid medical and environmental reasons for a test failure to occur.  Third, even sober people can and do fail standardized field sobriety tests.

Understanding the Walk and Turn

The basic premise of the walk and turn test is simple. Upon the officer's command—just like Simon Says Simon Do—the suspect will take nine steps, heel to toe, along a straight line. After the ninth step, the officer will direct them to slowly turn on one foot before returning along the same line.

During the test, there are 8 clues the officer will watch for. Each clue that is present is an indicator of intoxication, according to the test. These indicators include:

  • Starting the test too soon
  • Losing balance while receiving instructions
  • Stopping while walking
  • Failing to walk heel to toe
  • Stepping out of line
  • Lifting arms to balance
  • Taking the wrong number of steps
  • Turning improperly.

All of these observations are subjective. Different people could reach different conclusions when determining if a person was unbalanced during instructions or stepped off of a line during the field sobriety test.

Valid Reasons for Failing the Test

There are also other explanations for a poor result on the walk and turn test that are unrelated to intoxication. Any one of these factors could lead to a false-positive result during a walk and turn test.

Some factors that could lead to a failed test include:

  • Improper attire: The wrong footwear could cause a person to fail a walk and turn test. Flip flops and high heels in particular often lead sober people to fail this test.
  • Cognitive issues: Tests designed to identify intoxication can also unintentionally target other issues. Elderly and persons with developmental disabilities often have trouble completing this test while someone with a brain injury could struggle to understand the instructions.
  • Poor surfaces: The walk and turn test is designed to occur on a perfectly flat surface. At some traffic stops, flat surfaces are not available.
  • Distractions: Other distractions like flashing lights or heavy traffic could trigger a failure during a test as opposed to intoxication.

Speak with a Board Certified Houston DWI Defense Attorney

Attorney Doug Murphy has had repeated success highlighting problematic field sobriety test results and shining the light on reasonable doubt.   If you face a DWI charge in Houston, contact the Doug Murphy Law Firm, P.C. to discuss if faulty field sobriety tests were a factor in your case.

About the Author

Doug Murphy

Doug Murphy is one of only two Texas lawyers Board Certified in Criminal Law by the Texas Board of Legal Specialization, and also in DWI Defense by the National College for DUI Defense, accredited by the American Bar Association and the Texas Board of Legal Specialization.


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