Since the state passed the "per se" blood alcohol law in 2003, defining blood alcohol of .08 or higher as a crime, rather than as only a presumption of intoxication, defense attorneys have had great success challenging blood alcohol tests in court, according to a January 22 article in Mass. Lawyers Weekly. Defense lawyers are demanding expert testimony on both the validity of the tests and the maintenance of the machines, and when it is lacking, judges are often excluding the breath test evidence.
Prosecutors believe that expert testimony should not be routinely required and have appealed the exclusion of blood alcohol test results in two cases still pending in lower courts. Yesterday, the Supreme Judicial Court held oral arguments in the cases, Comm. v. Thomas and Comm. v. Colturi. According to the February 8 Boston Globe, a key issue is how to extrapolate from the blood alcohol at the time of the test to the blood alcohol at the time of the stop, which may have been one hour or more earlier.
More information on drunk driving laws in Massachusetts is available at Mass. Law About Drunk Driving.