Wetmore Road is closed, just east of Interstate 10, due to a two-vehicle crash that seriously injured one person.
The crash happened in the 2400 block of West Wetmore Road, where it curves into North Highway Drive, said Capt. Adam Goldberg, a Northwest fire spokesman.
The 18-year-old driver of a Ford Mustang lost control of the car and crashed into a tree and a parked car, Goldberg said.
The driver's 18-year-old girlfriend had to be extricated from the car and was taken to the trauma center at University of Arizona Medical Center in serious but stable condition.
The driver had minor injuries and was treated at the scene.
Neither person was wearing a seatbelt, Goldberg said.