Idaho State Police and other agencies responded to a rollover accident on Interstate 15 at the Clark Street exit.
The accident happened just before 12:00 p.m., Thursday.
Photos show a white passenger car on its top in the median.
ISP says Colton Stears, 19, of Chubbuck was driving south in a Honda Civic when the car veered to the left and hit the side of a hill. Stears' car rolled and came to rest on its top.
Stears was wearing a seat belt. He was taken by ambulance to the Portneuf Medical Center.
The southbound off-ramp was blocked for approximately one hour as crews worked to free Stears from the car.