Police in New Jersey have many ways to build a case for driving while intoxicated (DWI). They can establish probable cause for an arrest by instructing a suspect to perform field sobriety tests (FSTs). A “perfect” performance on FSTs is essentially impossible and is unlikely to help someone avoid arrest regardless. Defending against New Jersey DWI charges that include alleged failed FSTs means challenging whether police officers correctly administered the tests. A Pennsylvania town recently sought volunteers for an unusual form of police training. New Jersey police have not yet asked for volunteers to get drunk so officers can practice administering FSTs, but the outcome of the Pennsylvania training may change that.
State law allows prosecutors to make a case with evidence of impairment besides blood alcohol content (BAC). The DWI statute defines the offense, in part, as driving a motor vehicle “while under the influence” of alcohol or drugs. Eyewitness testimony from officers, including FST performance, is often the main evidence presented by the state.
The National Highway Traffic Safety Administration (NHTSA) has established a set of standardized FSTs that most states have adopted. The set of standardized FSTs consists of three tests:
1. One-Leg Stand: The suspect must raise one foot about six inches off the ground and hold it there.
2. Walk and Turn: The suspect must walk a straight line, keeping their heel to their toe with each step, for a total of nine steps. Then, they must turn 180 degrees and repeat the process until they return to the starting point.
3. Horizontal Gaze Nystagmus: The officer holds a pen or other object at a constant distance from the suspect’s face while moving it from side to side. The suspect must follow the object with their eyes without moving their head. The officer is looking for involuntary eye movement, known as nystagmus, supposedly associated with intoxication.