WRENTHAM -- A state trooper, whose life was said to have revolved around his seven children, was killed just before sunrise Thursday when his cruiser struck an unoccupied dump truck on Interstate 495 near Route 1A.

Trooper Paul F. Barry, 39, of Franklin, was remembered Thursday as a loving father who was admired by his peers.

Barry, a six-year veteran of the state police, helped disburse cruisers and train troopers in the state police fleet section, based at Fort Devens in Ayer, said Lt. Eric Anderson, state police spokesman.

`` He was really quite a family man and a loving father,'' Anderson said. `` Everything was about family in his life.''

The cause of the crash is under investigation, state police said. Barry was driving north on I-495 when his cruiser drifted into the breakdown lane and struck a six-wheeled dump truck parked in the breakdown lane south of the Route 1A exit around 4:45 a.m., Anderson said.

Barry was pronounced dead at Milford Regional Medical Center, Anderson said.

Traffic on I-495 and roads leading to it, including Interstate 95, was backed up for four hours after the crash, causing major delays for the morning commute, police said.

Plainridge Racecourse employee Paula Leuschner said she was stuck in traffic for about a half-hour, coming from Taunton.

Leuschner said she exited the highway early, and took Route 106 to her job in Plainville, but `` even 106 was backed up.''

Barry is believed to be the first state police officer killed in the line of duty locally in at least 10 years.

The last state police officer killed on duty in Massachusetts was motorcycle trooper Vincent Cila, 45, of Malden, who died while riding back to the Logan International Airport barracks with another trooper last July 25, state police said.

A memorial fund has been set up for Barry's children.

Donations may be sent to: the Children of Paul F. Barry Memorial Fund, 80 Franklin Village Drive, Franklin, MA 02038.

MICHAEL GELBWASSER can be reached at 508-236-0372 or at mgelbwasser@thesunchronicle.com.