Two other people in the car were injured. All four were from Colorado.
The Arizona Department of Public Safety says the crash happened on westbound Interstate 40 about 10 miles west of the town of Kingman.
The Arizona Highway Patrol says the car, a black 2003 Nissan, rolled one-and-a-half times and two people were thrown out.
Both 19-year-old Damon R. Johnson of Pine, Colo., and 20-year-old Katelyn M. Henning of Littleton were pronounced dead at the scene.
Authorities say the driver, 20-year-old Andrew Schall of Bailey, Colo., was treated for minor injuries and released.
The other passenger, 19-year-old Nichole Franco of Littleton, was admitted to a hospital in Las Vegas. She is in critical but stable condition.
CSU says Henning and Schall were students.
Investigators say only the driver was wearing a seat belt and the two victims may not have died if they had been wearing their seat belts.
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