Twenty-three students heading to Boston on a field trip sustained minor injuries Wednesday morning in a school bus crash in Bedford, Mass.

NBC Boston reports that the bus was carrying about 40 students on Route 3 when it collided with a van towing a trailer around 9 a.m.

Police say the crash occurred when an unidentified vehicle abruptly changed lanes in front of the bus; the bus driver applied his brakes, and the van was unable to stop before hitting the rear of the bus.

The Lowell School Superintendent's Office says the bus was one of eight from the Bartlett Community Partnership School in Lowell that were heading to Boston for a field trip to the Boston Symphony Orchestra.

The injured students were taken to local hospitals for further evaluation. The students who were not injured were taken off the highway and returned to the school.

The bus driver was hospitalized for minor injuries. The driver of the van was not injured.

The car reported to have cut off the bus has not been found.

Video from NBC Boston: