In order to convict someone of driving while intoxicated (DWI), New Jersey prosecutors must prove beyond a reasonable doubt that the person was impaired by alcohol or drugs. State law allows police to collect breath samples to test blood alcohol concentration (BAC) in suspected DWI cases. Police in New Jersey typically use a device known as an Alcotest, which analyzes breath samples provided by blowing into a tube. These devices require careful maintenance and calibration in order to produce reliable measurements. In October 2017, prosecutors in several New Jersey counties notified thousands of individuals with DWI convictions or pending charges that police may have mishandled BAC evidence in their cases. A specially appointed judge will determine whether any New Jersey DWI cases should be reviewed in light of this alleged misconduct.
New Jersey law creates an incentive for prosecutors to rely on BAC evidence. They can prove that a defendant was legally impaired through circumstantial evidence, such as an arresting officer’s testimony about a DWI defendant’s behavior and appearance. New Jersey’s DWI statute creates a presumption of impairment, however, when a defendant’s blood alcohol concentration (BAC) was 0.08 percent or higher at the time of, or within several hours of, their arrest. Penalties are also higher for first-time DWI convictions if the defendant’s BAC was 0.10 percent or greater.
The Alcotest device purports to measure the concentration of alcohol in a person’s blood by performing tests on samples of that person’s breath. This requires a certain amount of extrapolation using algorithms in the device’s programming. The device uses infrared technology and the process of electrochemical oxidation to test breath samples. This latter process is particularly sensitive to environmental factors like temperature and potential contaminants. The New Jersey Supreme Court’s 2008 decision in State v. Chun, in which we represented several appellants, established guidelines for the maintenance and calibration of these devices, as well as documentation to indicate when an Alcotest device was most recently serviced.