Police officers in Massachusetts have relied on alcohol breath tests to detect alcohol consumption among drivers for years. The results of the test can justify arresting people, and the readings often provide what the courts consider factual evidence of operating a vehicle under the influence of alcohol. The breath test devices, however, have not produced much confidence when investigators scrutinize their accuracy. Hardware failures, out-of-date software and user errors all have the potential to skew results and create unfair convictions.
An investigative report by a major newspaper cited a lack of transparency among breath test manufacturers as a barrier to confirming their accuracy and reliability. Manufacturers guard their proprietary secrets closely and frequently withhold technical information about the devices. Even when devices might perform properly, personnel at police stations might not calibrate the machines or update software as necessary.