New Jersey’s driving while intoxicated (DWI) statute allows the state to prove that a defendant was impaired by alcohol with the results of blood alcohol content (BAC) testing. A BAC of 0.08 percent or higher creates a legal presumption of impairment. Police can determine BAC by testing a sample of breath, blood, or urine. Breath testing is considered to be the least intrusive. Blood and urine tests must follow the rules established by the Fourth Amendment for searches. A defendant can challenge the admissibility of BAC evidence by establishing a violation of their Fourth Amendment rights. A 2013 U.S. Supreme Court decision specifically addressed warrantless blood draws in DWI cases. The New Jersey Appellate Division cited that decision earlier this year in State v. Smijean, reversing a DWI conviction that involved BAC evidence from a warrantless blood draw.
Breath testing for BAC requires a person to blow into a tube attached to a testing device commonly known as a breathalyzer. Most New Jersey police departments use a device known as an Alcotest. Submission of a breath sample is mandatory for anyone who drives on a public road in New Jersey, and refusal to submit a breath sample upon request by law enforcement is a separate motor vehicle offense.
Since breath testing only requires blowing into a tube, it is not considered a “search” under the Fourth Amendment. Blood testing, however, is considered intrusive enough to fall under the Fourth Amendment’s prohibition on warrantless searches. Drawing a person’s blood therefore requires that person’s consent or a warrant issued by a judge. In a general sense, police may be able to conduct a search without a warrant if they can establish that “exigent circumstances” made it impractical to obtain a warrant first, usually because of the risk of loss or destruction of evidence. How this exception applies in DWI cases has been a matter of dispute.