Drivers in Florida who are suspected of DUI / DWI are typically told to take a field sobriety test such as the one-leg stand test during a traffic stop. However, the test doesn’t help police decide whether to make a drunk driving arrest. Field sobriety tests exist solely to provide probable cause for an arrest and create evidence for a drinking and driving court case.

The one-leg stand test is one of three standardized field sobriety tests recognized by the National Highway Traffic Safety Administration (NHTSA). Many drivers worry that a poor performance on the one-leg stand or another field sobriety test dooms them to a slam-dunk conviction, but that’s far from true. A skilled Florida attorney who focuses on drunk driving defense will effectively challenge the results of the one-leg stand test as part of a comprehensive defense strategy.

The one-leg stand test begins when an officer directs a driver to listen to the instructions while standing with feet together and arms down. The officer then instructs the driver to raise one leg about six inches while holding his or her foot parallel to the ground. The driver must look at his or her foot while counting “one thousand one, one thousand two …” until directed to stop. The test usually lasts about 30 seconds.

As the driver performs the one-leg stand test, an officer is looking for four signs of impairment – hopping on one foot, using the arms to balance, swaying while balancing, and putting his or her foot down three or more time during the test. If the officer notes two or more of these signs, he or she will assume that the motorist has a blood alcohol content (BAC) of .10 or greater, and the driver will be arrested for DUI / DWI.

The one-leg stand test, like other field sobriety exercises, is a divided-attention test – it requires a driver to concentrate on two tasks at once.  Prosecutors will argue that any variation between the way the officer explained the test, and the way in which the driver performed the test, is clear evidence of mental or physical impairment. 

However, many field sobriety tests, including the one-leg stand test, are inherently flawed, because mere physical impairment alone is classified as a sign of intoxication. To understand why this is important, it’s useful to know how alcohol affects the central nervous system. Alcohol causes both mental and physical impairment, but mental impairment always occurs before any physical problems. Physical impairment can be masked in those with a high tolerance for alcohol, but mental impairment cannot be disguised. If no mental impairment is displayed, then any physical impairment must be attributed to factors other than alcohol.

In order to successfully pursue a drunk driving charge, prosecutors must show that the driver was both mentally and physically impaired. An experienced DUI / DWI attorney can attribute all four signs of intoxication indicated in the one-leg stand test to physical impairment caused by illness, injury, or other factors.

Even drivers who haven’t had anything to drink can have difficulty standing on one leg for 30 seconds. The one-leg stand test is considered especially challenging for motorists with back or leg injuries, drivers over 65, individuals with inner-ear disorders or other balance problems, and those who are overweight. Uneven ground or heels higher than two inches can skew the test results even further.