A bus carrying a Connecticut prep school lacrosse team overturned Monday on the way to a match, shaking up the team and causing four people minor injuries, state police said.

The accident on Route 9 in Middletown involved a bus carrying 15 people with the Williams School junior varsity lacrosse team. The team was on its way from New London to Waterbury for a game against Chaise Collegiate.

State police said the northbound lanes of the four-lane highway were closed after the 3 p.m. accident. Several ambulances were called, but the four injuries were minor, State Police Trooper William Tate said.

No other vehicles were involved in the accident, police said. The cause of the accident was not immediately known.

The incident comes less than two months after a March 2 accident in Atlanta that killed seven people, including five members of the Bluffton (Ohio) University baseball team. Twenty-eight were injured.

Investigators said the bus driver apparently mistook the ramp for a regular highway lane, traveling up it at "highway speeds." The bus than crashed into a concrete barrier at a T-intersection at the top of the ramp, flipped off the overpass and fell 30 feet back onto Interstate 75.