Prosecutors in New Jersey may offer two types of evidence to prove guilt in driving while intoxicated (DWI) cases. First, they may introduce testimony from police officers and others who witnessed a defendant’s appearance and demeanor. This may include testimony about field sobriety tests, or testimony from officers trained as drug recognition experts. The second method allowed by the New Jersey DWI statute is evidence of blood alcohol content (BAC) of at least 0.08 percent. Most police departments in New Jersey use a device known as the Alcotest to collect breath samples and test them to determine a DWI suspect’s BAC. A landmark 2008 decision by the New Jersey Supreme Court, State v. Chun, established standards for the use of these devices in order to maximize their accuracy. One rule created by the Chun decision requires women who are over sixty years of age to provide a smaller breath sample than other people, based on findings that women at that age are generally unable to provide as much breath as their male peers. A 2013 follow-up order in the Chun case limited the state’s ability to prosecute women over the age of sixty for refusal to submit a breath sample.
New Jersey’s implied consent statute requires drivers to submit to breath testing in DWI investigations. Refusal to do so is a separate motor vehicle offense, punishable by fines and driver’s license suspension. The Alcotest requires an individual to blow into a tube connected to the device for a sustained period of time, in order to provide the 1.5 liters of air needed for the test. The individual must seal their lips around the tube so that no air escapes while they are blowing. New Jersey courts have held that an individual may be found guilty of refusal for repeatedly failing to provide an adequate breath sample, such as by failing to seal their lips around the tube or failing to blow for long enough.
Prior to the 2008 ruling in Chun, a court-appointed special master issued a report that recommended various standard procedures for administering the Alcotest. This included the 1.5-liter minimum volume of air. The special master also noted that the evidence supported a lower required volume for women older than sixty. The court reviewed research showing that, after age sixty, women’s average volume of breath was 1.4 liters. This average volume decreased by 0.1 liter every ten years afterwards. The court accepted these findings and ruled that women over the age of sixty must only provide 1.2 liters of air. It also dismissed possible objections to the two standards under the Equal Protection Clause.