Supreme Judicial Court (April 18, 2007)

In a decision eagerly awaited by prosecutors, the SJC ruled today that, where the Commonwealth proceeds on a "per se" theory of operating under the influence, prosecutors are not required to present expert testimony on retrograde extrapolation to admit a breath test result if the test was given within 3 hours of the arrest.

When proceeding only on an "under the influence" theory with a breath test result, the Commonwealth is required to present expert testimony establishing a relationship between the test results and intoxication as a foundational requirement of the admissibility of such results.

A State trooper stopped the defendant at 9:10 P.M. after observing her operating her vehicle in an unsafe fashion. The trooper smelled alcohol in the car and on the defendant and noticed that her speech was slurred and her eyes glassy. She swayed, was off balance, and used her car for support as she walked. The trooper arrested the defendant for operating a motor vehicle while under the influence of alcohol (OUI) and she consented to a breathalyzer test. Police administered two tests, the first at 10:15 P.M. and the second at 10:19 P.M. The results showed a blood alcohol level of .15 percent. The defendant was charged with violating the OUI statute by operating a vehicle "with a percentage, by weight, of alcohol in his or her blood of eight one-hundredths or greater, or while under the influence of intoxicating liquor."

After a motion in limine filed by the defendant to limit the admissibility of the breath test result, the judge ruled that "the Commonwealth may not offer evidence of a breathalyzer test result obtained more than an hour after evidence of the defendant's last operation of a vehicle to prove the 'per se' offense unless it offers expert [retrograde extrapolation] testimony establishing the defendant's blood alcohol at the time of operation ... [and] ... may not offer [such test result] to prove the 'impaired ability to operate' offense unless it offers expert testimony establishing [both] the defendant's blood alcohol level at the time of operation and the significance of that level as it pertains to impairment." The Commonwealth filed an interlocutory appeal of the judge's decision.

The SJC ruled that retrograde extrapolation testimony is not required to admit the results of a breath test so long as the test is conducted within a reasonable period of time after the driver's last operation of the vehicle. The court defined a reasonable amount of time as 3 hours.

Additionally, if the Commonwealth charges the per se and under the influence theories in the alternative and proceeds to trial on both, the breath test result is admissible without expert testimony. The Court reasoned that in such a case, the jury would be instructed that if they find the defendant operated a motor vehicle with a blood alcohol content of .08 or greater, he is guilty of violating the OUI statute, and if they do not so find, they may still consider whether he violated the statute by operating while under the influence of intoxicating liquor. However, the court ruled that, in the unlikely event that the Commonwealth chooses to proceed only on an under the influence theory and intends to offer evidence of a breathalyzer result of .08 or above, it must offer expert testimony on the significance of that level as it pertains to impairment.