RICHFIELD (AP) — The State Patrol says one of its troopers was injured by a drunk driver who hit his squad car.

It happened Saturday night in Richfield on the exit ramp from westbound Interstate 494 to northbound Interstate 35W.

The Patrol says two squad cars were at the scene of an unrelated crash. Both had their emergency lights activated, and flares were lit to alert drivers. The Patrol says that's when a drunk driver sideswiped the first squad car and then rear-ended the second.

The trooper in the first squad was not injured. The trooper in the second, Allen Thill, was taken to a hospital, treated and released.

Lt. Eric Roeske says the driver failed a preliminary alcohol test and was arrested, while a passenger in his car suffered minor injuries.

Copyright 2013 The Associated Press.