This week St. Charles DWI lawyer Todd Ryan provides insight into the One Leg Stand test. The One Leg Stand is the third of the three Standard Field Sobriety Tests (SFSTs) used by law enforcement to determine probable cause to arrest drivers for Driving While Intoxicated (DWI). Similar to the Walk-and-Turn test, the One Leg Stand is a divided attention test with an instruction stage and a performance stage.
It’s very important for drivers to understand that like the other SFSTs, the One Leg Stand test was developed in laboratory conditions. In particular, the One Leg Stand test is difficult to complete for people who are 65 years or older; have back, leg, or inner ear problems; or are overweight by 50 or more pounds. The research also suggests shoes with heels greater than two inches will invalidate the test results, so drivers should be given an opportunity to remove their shoes. Other environmental factors can cause false positives as well. Extreme cold or heat, slippery or icy surface, uneven surface, and busy or dangerous roadside conditions can affect a person’s ability to complete the One Leg Stand test successfully.
The law enforcement training manual produced by NHTSA indicates the length of this test is particularly important. NHTSA instructions require the driver to keep his or her foot raised for 30 seconds. The research suggests many impaired individuals can maintain the raised-foot position for 25 seconds but will have difficulty maintaining the position for 30 seconds.