Lights flashing in the rearview mirror are often an indication that the Illinois driver needs to pull over. Once this occurs, the officer will usually ask for the driver's license and registration. Throughout this process, the law enforcement officer is analyzing the situation to determine if there are other issues such as possible drunk driving that need to be addressed.
If the officer suspects that the driver has been drinking, he or she will most likely ask the driver to participate in one or more field sobriety tests. These tests allow the officer to observe the driver's eye movement, balance and other factors that may indicate a problem. These observations then alert the officer to the need for further testing and possible arrest.
One of the usual field sobriety tests is the Horizontal Gaze Nystagmus. With this test, the officer can monitor the driver's eye movement to determine if such movement is outside of the parameters for a driver with no impairment. Another common test if the Walk and Turn. This test allows the officer to monitor the individual's balance and attention. Yet another test, the One-Leg Stand, also allows the officer to monitor the driver's balance.
These tests often play an essential role in the officer's decision to arrest an Illinois driver for drunk driving. Statistics indicate that when all three portions of the test are used, they are reliable approximately 90 percent of the time. However, they are still subject to challenge in court. When an Illinois driver is arrested based upon this type of data, he or she will want to work with an experienced attorney to decide the best way to address the charges and the results from this type of testing.