Lubbock police say the Deputy was going west on Marsha Sharp, when his SUV left the left side of the freeway, and came to rest at the bottom of the overpass.
The SUV was upside-down when emergency crews responded. The Deputy was alert and conscious, and EMS said his injuries were moderate.
The Deputy was the only person in the SUV. He was not in pursuit, and there were no other cars involved.
The Sheriff's Office is conducting the investigation.