Field Sobriety Tests, Alcosensors and Breathalyzers

When a police officer has reasonable suspicion to believe that a motorist is driving a vehicle under the influence of alcohol, the officer will pull the driver over. At that point, the officer will administer field sobriety tests, such as the Horizontal Gaze Nystagmus evaluation (the "eye test"), the walk and turn evaluation and the one leg stand evaluation. The two coordination tests will be used by the officer as a basis for him to argue the driver is impaired, even though the tests were designed to determine the probability of whether the driver has a blood alcohol concentration level of .008 grams or more. Field sobriety tests are basic coordination and reaction tests that allow the officer to judge whether the driver is impaired. During a field sobriety test, the officer may ask the driver to walk a certain number of paces heel-to-toe, to balance on one leg, to recite portions of the alphabet, or other coordination or reaction tests.

The officer may also administer a portable breath test (PBT) such as the Alcosensor and although the PBT does not provide an official measurement of alcohol in the driver’s blood for legal purposes, it will provide a result that indicates whether the officer should arrest the person to verify the PBT’s measurement with an official breath, blood or urine test.