Updated

More than 40 people were injured Friday when two tour buses carrying high school students home to New Jersey collided on Interstate 95, authorities said.

The accident happened when one bus developed mechanical problems and slowed down to pull over, according to Trooper B.O. Johnson of the North Carolina Highway Patrol.

A trailing bus struck it from behind, he said.

The second bus slid over the shoulder of the highway and down an embankment, crushing its front end and trapping the driver. Students escaped through an emergency exit, Johnson said.

The driver, Ozell Robertson, 61, of Columbia, S.C., was taken to a hospital by helicopter, Highway Patrol spokesman Lt. Everett Clendenin said. No details on his injuries were immediately available.

Robertson was charged with a speed violation and may face more charges, Clendenin said.

The buses were among three carrying students high school students home to Newark, N.J., from a graduation trip to Florida, officials said.

Jennifer Franklin, spokeswoman for Betsy Johnson Regional Hospital in Dunn, said two students remained in the hospital overnight for observation.