Police say at about 4:35 a.m., two women were traveling north on Wasatch Boulevard at about 5100 South.
Police say the driver lost control and the car rolled and burst into flames.
Police say the driver was able to get out of the car, but the passenger was not, and died at the scene.
The driver was taken to a local hospital with minor injures.
The cause of the crash was under investigation, but police said speed may have been a factor. Thay also said that drugs or alcohol were not factors in the crash.
Police later identified the deceased victim as 19-year-old Kellie McElroy of Salt Lake City. Police also indicated that the 18-year-old driver is McElroy's cousin.
Sections of the road on Wasatch Blvd. were still closed by 9:30 a.m., and police said the road may remain closed a few more hours into the afternoon as they work to clear the scene.