DUI and DWI are illegal offenses of driving a vehicle while impaired by alcohol or drugs like opium, cocaine, etc. DUI refers to driving under the influence which is impaired by the drugs. DWI refers to driving while intoxicated which is impaired by the alcohol consumption.

There are sobriety tests for evaluation of candidate for DUI and DWI offenses which include:

Field sobriety tests
Field sobriety tests are performed to identify an individual who is driving the vehicle under the influence of drugs or alcohol. These tests were performed by the police officer. The police officer has the right to stop the vehicle and ask individual to take field sobriety tests if he suspects that the individual is driving under the influence of drugs or alcohol. These tests include:

  • Walk and turn test – Police officer will ask you to take this test if he suspects you have been drinking while driving. He may ask you to walk in a straight line and come back. This test is performed to measure individual’s balance and ability to follow instructions.
  • One leg stand test – This task is performed to examine the individual’s balance but it is will not give accurate results in neurological disorder patients. In this, police officer will ask you to stand on one leg. Individual with drunk driving can not balance on one leg. This will give false results in patients with Parkinson disorder.
  • Horizontal gaze test – In this test, the officer will place an object about one feet from the individuals face. Then he moves the object from one side to other to observe eye movements. If an individual is rotating eyes with jerking then he or she is in a drunken state.

Breath alcohol test
This test is performed to measure alcohol content in your breath. This is performed by using a device called breath analyzer. The police officer will ask you to perform breath test. With each breath you take, you take oxygen and release carbon dioxide which contains the concentration of alcohol in your breath. This can be detected by the breath analyzer.

Blood or urine sample tests
These tests are performed to measure the concentration of alcohol in blood and urine. This gives accurate results but it is time consuming. In this, blood or urine samples are taken from the individual and send to the laboratory to measure how much concentration of alcohol is present in blood or urine samples.