Officer Bruce St. Laurent, 55, was a 20-year veteran of the Jupiter Police Department and one of several officers from agencies across Palm Beach County helping with security for the president's visit.
He was ahead of the motorcade on Interstate 95 preparing to shut down the highway when he was hit by the Ford F-150, Palm Beach County Sheriff's spokeswoman Teri Barbera said. He was taken to nearby St. Mary's Medical Center and was pronounced dead.
Jupiter Police spokesman Sgt. Scott Pascarella, told The Palm Beach Post (http://bit.ly/QdMZwr ) he trained St. Laurent when he was a new officer.
"We didn't lose a co-worker. We lost a friend," Pascarella told the newspaper. "He would do anything for anyone."
Barbera said an investigation was ongoing and no charges had yet been filed against the driver.
Obama was on the second day of a bus tour through the key swing state and made a campaign appearance Sunday at the Palm Beach County Convention Center.
White House press secretary Jay Carney said the president didn't see the accident, but he was notified of the officer's death and said "our thoughts and prayers are with the officer's family."
The Post also reported that St. Laurent had been a motorcycle officer for 18 years and in 2005 he earned a Distinguished Service Award by the Traffic Safety Committee of the Palm Beaches.
The newspaper reported that tn 2001, he was injured when a vehicle he was chasing suddenly stopped and he rammed into it. The two occupants were later arrested, one on a charge of driving with a revoked license and the other for having an outstanding warrant for reckless driving.