New Jersey prosecutors often rely on evidence of a defendant’s blood alcohol concentration (BAC) to prove guilt in driving while intoxicated (DWI) cases. Police officers typically determine a person’s BAC by testing a breath sample. All police departments in this state use a device known as the Alcotest for this purpose. The Alcotest is prone to errors, and it requires continual maintenance. We were involved in a New Jersey Supreme Court case, State v. Chun, that established specific procedures police must follow to maintain the Alcotest device. Failure to follow these procedures ought to result in suppression of the breath testing results. A pending lawsuit in a New Jersey federal court is calling thousands of Alcotest results into question due to allegedly fraudulent records. The plaintiff in Ortiz v. New Jersey State Police claims that thousands of DWI defendants throughout the state would have challenged the BAC evidence in their cases, had they known about the alleged failure to follow the procedures established by Chun.
Prosecutors can establish the required elements of DWI without BAC evidence, but state law gives them a compelling reason to prefer such evidence. A defendant with BAC of 0.08 percent or higher—commonly known as the “legal limit”—is presumed to be impaired within the meaning of the DWI statute. BAC of 0.10 percent or higher can result in even greater penalties. Anyone driving a vehicle on public roads in New Jersey, according to state law, has given implied consent to provide a breath sample on suspicion of DWI, and refusal to do so is a separate motor vehicle offense.
Devices that purportedly use a breath sample to measure BAC first appeared in the mid-20th century. The Alcotest 7110 MKIII-C became the device for New Jersey law enforcement during the early 2000s. It uses two methods to measure BAC: infrared spectroscopy and electrochemical cell technology. Regular maintenance and careful calibration are what the State says make the process reliable. The purpose of the Chun decision was to attempt to ensure that this happens.