Chemical testing for alcohol or drugs is a key component of most prosecutions for driving while intoxicated (DWI) in New Jersey. Breath testing is mandatory under state law, but the Alcotest and similar devices can only test for the presence of alcohol. If police suspect driving under the influence of drugs, New Jersey law provides no immediate means to obtain evidence. Drawing blood without a person’s consent requires a warrant in most circumstances. The New Jersey Appellate Division took up these issues in an appeal that challenged the admissibility of blood test results. Its ruling in State v. Nasta deals specifically with criminal charges, rather than DWI, but it is likely to affect New Jersey DWI cases in the future.
Since it involves an invasive procedure, courts have held that drawing blood as part of an investigation for DWI or another offense is a “search” within the meaning of the Fourth Amendment to the U.S. Constitution. This means that police must obtain a warrant from a judge by demonstrating that they have probable cause to believe that the search will reveal evidence of wrongdoing.
Police are not required to obtain a warrant in certain situations identified by courts as exceptions to the Fourth Amendment. One exception involves “exigent circumstances,” in which taking the time to obtain a warrant would risk greater harm than a warrantless search. The impending destruction or loss of evidence could constitute an exigent circumstance. The U.S. Supreme Court, however, ruled in Missouri v. McNeely that the natural breakdown of alcohol by the human body is not “exigent” enough to allow a warrantless blood draw. The court has not said that a warrantless blood draw is never justified by exigent circumstances, but it has not identified what those circumstances might be.