On Tuesday, a the driver of a car was killed after being involved in a single-car crash in Oklahoma City.

Oklahoma City Police said the man driving the car possibly had a medical issue or had fallen asleep at the wheel when the car he was driving went off the road. His car went into the retaining wall on Interstate 35 around Wilshire Blvd.

Oklahoma Highway Patrol is saying that the man’s name that was killed in a single-car crash has not been released.