The final SFST is the One Leg Stand (OLS) test. Like the other two before it, NHTSA has spent time and money over the years testing this test, and has statistics that show it is 83% accurate. As with the others, there are reasons to doubt those statistics that are beyond the scope of this post.
The One Leg Stand test is what it sounds like. The officer has the driver stand on one leg with their arms at their side and count out loud until told to stop. There is an instruction stage and a “balance and counting” stage. During the instruction stage, the driver has to stand still with their feet together (as opposed to heel-toe like before) with their arms at their side. The officer tells the driver to lift either his left or right foot about 6 inches off the ground with both legs straight and the raised foot parallel to the ground. The driver is then to count out loud “one thousand one, one thousand two, one thousand three” and so on until told to stop. Unbeknownst to the driver, the officer is taught to keep the driver counting to at least “one thousand thirty.” If the officer stops the driver before then, the test is significantly less accurate according to NHTSA.
There are four clues the officer is taught to look for during the OLS. They are:
- Swaying while balancing
- Using arms to balance
- Hopping
- Putting the lifted foot down on the ground
Here is an example of a more narrative description of the OLS test results in a Mississippi police report for a DUI arrest:
