Judges in New Jersey may order an ignition interlock device installed in the vehicles of first-time or repeat offenders convicted of DWI. Designed to detect a motorist’s blood alcohol level, the device prohibits a vehicle from starting if the individual’s BAC is more than 0.05%. While IIDs may use advanced technology to accurately determine a BAC before allowing a car to start, many roadside breath test devices allegedly do not have the same degree of accuracy.

An investigation conducted by The New York Times revealed that in 2019, judges in Massachusetts and the Garden State tossed more than 30,000 faulty breath test results from their cases. The investigation noted the “alarming frequency” at which some roadside devices produce inaccurate BAC readings.

Faulty test results and wrongful arrests

Roadside breath test devices have provided law enforcement officials with too many unreliable results. Motorists who submitted to roadside breath tests may have shown skewed BAC results up to 40% greater than their true impairment levels. When the result shows 0.08% or more, however, a motorist faces an immediate arrest followed by a DWI charge. The arresting officer may also have the driver’s vehicle impounded.

How a breath test device determines BAC

Many roadside breath test models rely on fuel cell sensors to detect how much alcohol an individual may have had to drink. The sensors react to a motorist’s breath when he or she blows into it and generate an electrical current. The strength of the current determines the BAC.

The test results, however, may skew if a driver had any breath mints or used mouthwash before an officer pulled over his or her vehicle. An improperly calibrated device may also prove inaccurate.

Faulty evidence and erroneous charges

When the legal system uses misinterpreted evidence based on inaccurate breath test results or a poorly calibrated roadside device, erroneous charges and subsequent guilty pleas may result. As many as 13,000 New Jersey motorists may have faced unsubstantiated DWI charges because of faulty evidence. Contesting a DWI charge and avoiding a conviction may prove successful based on the type of breath test device used.