Field Sobriety Tests
Historically, guilt was established by observed driving symptoms, such as weaving; administering field sobriety tests, such as a walking a straight line heel-to-toe or standing on one leg for 30 seconds; and the arresting officer’s subjective opinion of impairment. The officer must correctly perform the Field Sobriety Tests that are approved by the National Highway Transportation Safety Administration (NHTSA). The US Department of Transportation explains the Field Sobriety Test as, “a battery of three tests administered and evaluated in a standardized manner to obtain validated indicators of impairment and establish probable cause for arrest.” Starting with the introduction in Norway in 1936 of the world’s first per se law which made it an offense to drive with more than a specified amount of alcohol in the body, objective chemical tests have gradually supplanted the earlier purely judgmental ones. Limits for chemical tests are specific for blood alcohol concentration or concentration of alcohol in breath.