Once and officer has lawfully stopped a driver, he can do “preliminary” investigation to check for DUI or any other crime as long as he has reasonable suspicion. The officer can question the driver and will listen for statements that are signs of a possible DUI. During this traffic stop and preliminary investigation an officer can also conduct coordination tests, called Standardized Field Sobriety Tests and the results of these tests can help establish probable cause to arrest the driver for DUI. The three main tests which are advocated by the National Highway Traffic Safety Administration (NHTSA) are the HGN (horizontal gaze nystagmus), the walk and turn, and the one-leg stand. A driver may be asked to perform additional tests, but only these three tests are supported by scientific research.
It is important to know that a driver does NOT need to submit to any field sobriety tests. In fact, attorneys generally advise people not to submit to any field testing. The tests are structured to measure divided attention and have very specific instructions. Any deviation from any instruction will be used against the driver.
In addition to questioning and field sobriety tests, officers will make observations about behavior, lack of coordination, physical appearance and other details that can lead to a conclusion of possible impairment by alcohol or drugs. Some things that officers commonly list in their police reports are: bloodshot or watery eyes, slurred speech, stumbling or weaving, odor of alcohol, flushed face, inability to follow directions, slow reaction of pupils, abusive speech, uncoordinated movements when exiting a vehicle, leaning, imbalance, and sleepiness.
Any driver who is stopped for a possible DUI should remember that it is best to request to speak with a DUI attorney before answering any questions by a police officer. If you are subsequently arrested, again, you should request to speak with an attorney in order to protect yourself and your rights.





