New Jersey’s driving while intoxicated (DWI) law allows police and prosecutors to establish that a person was legally impaired by alcohol or drugs in a variety of ways. This includes testimony from arresting officers about a defendant’s appearance and behavior, such as an odor of alcohol, bloodshot eyes, slurred speech, and so forth. Police may ask a driver to perform one or more field sobriety tests (FSTs) in order to assess their condition and establish probable cause for an arrest. The federal government has recognized three “standard” FSTs, but New Jersey police may use other tests in DWI investigations. New Jersey courts may accept those tests as evidence, even though their reliability is highly questionable.
Standard Field Sobriety Tests
The National Highway Traffic Safety Administration (NHTSA) has established a Standardized Field Sobriety Test (SFST) battery consisting of three tests. Each test has standard instructions for police officers to deliver to drivers, as well as objective factors that indicate the possibility of impairment. At the same time, each test has serious shortcomings that make their reliability above average at best. The three tests are the “one-leg stand,” the “walk and turn,” and the horizontal gaze nystagmus (HGN).
The non-standard FSTs do not have these sorts of objective indicators. Instead, they rely to a great extent on the individual officer’s interpretation of how an individual performs. New Jersey courts may still accept non-standard FSTs as evidence, but they should not give them nearly as much weight as the SFST battery.