Matthew Cavanaugh for The Boston Globe

State Police troopers stopped cars at a sobriety checkpoint on Memorial Avenue in Chicopee.

Aram Boghosian for The Boston Globe

Trooper Mary Wakeham administered a sobriety test to a suspected drunk driver at a checkpoint along Route 16 in Everett.

Matthew Cavanaugh for The Boston Globe

A driver performed a sobriety test at a checkpoint in Chicopee.

Matthew Cavanaugh for The Boston Globe

A trooper held a portable breathalyzer at the Chicopee sobriety checkpoint.

Aram Boghosian for The Boston Globe

State Police Trooper Matthew Sheehan took a suspected drunk driver into custody along Interstate 93. A breath test later indicated the driver’s blood alcohol content was .17, which is above the legal limit. Sheehan was on “saturation patrol” looking for drunk drivers.

Aram Boghosian for The Boston Globe

A man was arrested for drunken driving at the Everett checkpoint.

Pat Greenhouse/globe staff

Judge W. Michael Goggins in Northampton District Court. He acquitted a defendant with a .13 breathalyzer test, saying, “I’m going to give you a break.”

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Judge Paul F. Healy Jr. retired from the bench in December 2010. His portrait hangs in a courtroom in Framingham District Court. He acquitted a defendant who caused a crash and admitted drinking four or five beers. An ER doctor testified the driver was “highly intoxicated.”

pat greenhouse/globe staff

Judge Thomas S. Barrett in Quincy District Court. He acquitted a defendant who got into an accident and told police, “I was driving, I’m drunk, and it’s all my fault.”

Pat Greenhouse/Globe Staff

Judge J. Thomas Kirkman at New Bedford District Court. Earlier this year he cited an outdated jury instruction that the breathalyzer has a margin of error of .01. The real margin of error is a small fraction of that.

Pat Greenhouse/Globe Staff

Judge James J. McGovern in Brockton District Court. He was charged with drunken driving in 1995 and was acquitted at a bench trial. Of 11 OUI bench trials he held in Bristol County in 2009 and 2010, he found all 11 defendants not guilty.

Pat Greenhouse/globe staff

Judge Robert G. Harbour in Marlborough District Court. He heard a case where the defendant’s lawyer was Daniel W. O’Malley. Because of the friendship between Harbour and O’Malley, the judge had been warned not to hear O’Malley’s cases.