When law enforcement officers on road patrol suspect that someone has been driving under the influence of alcohol (DUI), they will pull that person over. Typically, officers have some sort of reason for making the initial traffic stop.

Those reasons can include a driver who swerves, whose behavior seems erratic, or who has just pulled out of a bar or raucous party. When officers first approach the vehicle, they will ask you if you have had anything to drink.

Regardless of how you answer, if they suspect impairment because of your behavior, they may ask you to exit the vehicle. Knowing what they will do to determine impairment can help you better advocate for yourself during one of these traffic stops that could lead to a DUI arrest.

Police will typically perform a field sobriety test

If the police believe they have a reason to ask you to exit the vehicle, the first thing they will try to do is gather evidence of impairment. One thing they will do will be to perform the horizontal gaze nystagmus test as part of a field sobriety test.

In this test, they monitor your eyes for specific, jerking behaviors that indicate the presence of alcohol. After that, they may try to establish your memory, focus and balance. Having someone walk and turn, repeat certain information or stand on one leg can be part of a field sobriety test.

Officers may also request a chemical breath test

If your behavior during the traffic stop or your performance during the field sobriety test makes the officer strongly suspect impairment, they will likely request that you perform a chemical breath test.

Due to implied consent laws, refusing to perform the test when requested by officers can get you arrested on the spot. Although officers cannot compel you to perform the tests, they can still use the evidence from your driving and the field sobriety test as a means to bring DUI charges against you.