If Illinois police pull you over on suspicion of driving under the influence of alcohol, your anxiety level will undoubtedly rise. Everything from that moment may seem unfamiliar and confusing, and your impulse may be to just do what the officer tells you to do. However, this may not be the best plan of action.

Police rely on your sense of uncertainty during a traffic stop, and they may take advantage of your confusion to gather evidence to use against you. It is critical to know your rights and to react firmly and politely when an officer’s request steps over the line. One element of a DUI arrest during which you may be most vulnerable is the field sobriety tests.

What is the purpose of FSTs?

The results of your field sobriety tests determine whether police have enough evidence to arrest you for DUI. However, those results are often subjective. This means that if you participate in FSTs, you may be assisting police in building their case against you. If you fail the FST, police have cause to perform a breath test to determine whether your blood alcohol content is over the legal limit.

While Illinois law includes your implied consent to submit to a breathalyzer test after your arrest, the law does not obligate you to submit to FSTs. One study by the National Highway Traffic Safety Administration showed that standardized FSTs indicated driver intoxication with 91 percent accuracy when officers administer the tests correctly. Even if police improperly administer the tests, the results may still stand as evidence against you.

What are the standardized field sobriety tests?

The standardized field sobriety tests are those three challenges that the NHTSA has approved as the most reliable for determining if a driver is intoxicated. These are the three tests:

  • The horizontal gaze nystagmus: Officers watch for involuntary jerking in your eyes as you follow the movements of a pen or finger from side to side.
  • The one-leg stand: Officers watch for you to lose your balance as you stand on one foot and count to 30.
  • The walk and turn: Officers watch your balance, coordination and ability to follow a series of directions instructing you to walk heel-to-toe before turning and coming back.

Despite reports that these tests are accurate in their results, there are also many medical and environmental reasons why you may not be able to successfully complete any of them. Officers may also attempt to use other, non-standardized tests, such as asking you to tip your head back or touch your finger to your nose. You should know that these tests are unreliable, and your attorney should be aware if police based their probable cause to arrest you on any non-standardized tests or tests administered in less-than-ideal conditions.