Prosecutors Win Drunk Driving Challenge

The Supreme Judicial Court ruled yesterday in the cases of Commonwealth v Colturi and Commonwealth v. Thomas that prosecutors need not provide expert testimony to extrapolate from blood alcohol level at the time the test is taken to what it would have been at the time of a drunk driving stop. Lower courts had ruled in favor of defendants and required prosecutors to provide expert evidence, and prosecutors appealed. In its ruling in Colturi, the court held that "retrograde extrapolation" is not necessary to admit breathalyzer evidence, where the test is given up to three hours after the traffic stop, but that the exact length of time permissible in a given case should "fall within the sound discretion of the trial judge."