REVERE – Three days before Christmas Day, 1997, Patsy Juliano got the news that changed her life.Her 32-year-old son, Joseph Kennedy, had been killed that morning in a drunken driving accident in Carey Circle at one end of Revere Beach. Juliano and her family turned their mourning into action by getting involved with Mothers Against Drunk Driving, a cause that still brings her out to events like Thursday’s road sobriety reminder sponsored by the State Police down the beach from where her son died.”Please don’t let your family have a loss like ours did,” said the Peabody resident.Police arrested 4,838 drivers for operating under the influence in 2007, a 25 percent increase over the number of OUI arrests in 2006. As of May, 1,967 drivers were pulled over and arrested for operating while drunk on Massachusetts roads.In 2006, there were 174 alcohol-related driving fatalities across the state.”One out of three people know someone hurt or killed by a drunk driver,” said State Police Superintendent Col. Mark Delaney, “Stop, think and plan your summer activities: Make good, sound decisions.”State Police issue sobriety checkpoint alerts every week indicating areas of the state where they plan to crack down on drunken driving.State Police spokesman David Procopio said the checkpoints and the State Police Breath Alcohol Testing units, or “BAT Mobiles,” have helped boost arrest rates. The vehicles are equipped with cameras, satellite linkups and a pair of holding cells.Troopers assigned to the mobile police stations can complete the process of arresting a drunken driver in one-third the time it would take if the BAT was not assigned to a sobriety checkpoint.”It is a welcome addition to the force and is especially timely right before the July 4th holiday,” Delaney said, adding it is the primary responsibility of drivers and their passengers to ensure they drink responsibly or designate a sober driver.”We’re the ones who respond and pick up the pieces,” he said.