A semitrailer driver who veered off an exit ramp near Interstate 35 and flipped his truck onto its side was treated at Mary Greeley Medical Center Wednesday evening.

Although the driver was injured, he was conscious when officials arrived on the scene, said Iowa State Patrol Officer Heath Hove.

“The [Ames] Fire Department extracted him,” said Hove, at the scene of the accident. “He wasn’t able to get himself out.”

Officials do not yet know what caused the driver to skew off the road, although Hove said he planned to interview the driver shortly.

The driver of the semitrailer, who was described as a male in his forties, was the only person injured in the one-vehicle accident.

At about 10 p.m., a motorist on a cell phone reported a semitrailer lying on its side on Exit 111A, Hove said.

“A call came in of a semi on its side,” Hove said. “We don’t know how fast he was going.”

The speed limit of the exit ramp is 25 miles per hour.

Hove said approximately 30 to 40 minutes passed from the time the accident occurred to when the Ames Fire Department removed the man from the vehicle.

The Ames Police, Story County Sheriff’s Office, Iowa State Patrol and the Ames Fire Department responded to the accident.

The driver’s name has not been released at this time.