The SUV slammed into the outside retaining wall and rolled over, landing on its side.
The driver was the only person in the SUV. He was pinned under the side of the vehicle.
The Houston Fire Department managed to get the SUV off of him and he was transported to Ben Taub General Hospital in critical condition.
It was unclear why the driver lost control of the vehicle.
The accident shut down both sides of the West Loop for about two hours.
