The evidence used against defendants in DWI cases often seems overwhelming. But in reality, much of it can be effectively challenged. That includes both the chemical evidence obtained through breath, blood and urine and the evidence police obtain by observing you during your traffic stop and arrest.
Types Of DWI Evidence In New Jersey
When police make DWI arrests, they gather two kinds of evidence against suspected drunk drivers: chemical and observational. Chemical evidence consists of the results of breath, blood and urine tests. This is the evidence prosecutors tend to rely on the most, as it has the appearance of scientific certainty.
The other type of evidence is observational. This is the evidence police gather from observing your behavior, speech, appearance and the results of your field sobriety tests. The most significant aspect of observational evidence is the field sobriety testing. It typically consists of three parts: the horizontal gaze nystagmus (HGN), the walk and turn, and the one-leg stand.
Physical DWI Evidence
In the HGN, an officer watches your eyes closely for involuntary side-to-side movements indicative of alcohol consumption. In the walk and turn, you're instructed to walk a straight line, heel to toe, then make a tight turn and repeat the walk. The one-leg stand involves standing on one leg while counting to 30. The last two tests are designed to gauge your ability to apply mental and physical focus at the same time. Officers also frequently testify about subjective signs of intoxication at the time of arrest such as slurred speech, watery eyes, strange behavior and erratic driving by the defendant. Although an officer's descriptions may be entirely accurate, there may be legitimate explanations for some of the observed behavior. Slurred speech may be caused by any number of health conditions, as may watery eyes. “Intoxicated” behavior may be due to medications or mental health conditions.