GILA RIVER, Ariz. -- Westbound Interstate 10, south of Phoenix, has reopened after it closed on Tuesday morning because of a fatal collision.
The interstate was closed for hours, and traffic was backed up for miles.
According to the Arizona Department of Public Safety and the Gila River Indian Police, a truck collided with a passenger car.
According to investigators, a small white passenger car crossed from the eastbound lanes to the westbound lanes for unknown reasons -- directly into oncoming traffic.
The car slammed into a commercial truck.
The female driver of the car died at the scene. She has been identified as Areli Guzman Gonzalez, 28, of Mesa, Ariz.
"The driver of the commercial truck was not injured," said Capt. Brian Preston with the Arizona Department of Public Safety.
Officers still don't know what caused the fatal crash. Among the possibilities -- Gonzalez could have fallen asleep, had a medical condition or was distracted.
"There isn't anything that they're seeing at the scene that gives a quick and easy answer to any of those questions," said Capt. Preston.
The westbound lanes of I-10 were closed for more than three hours.
The highway was closed westbound at milepost 176 at the State Route 587 junction, approximately 25 miles southeast of downtown Phoenix.
The crash happened near mile marker 173. Drivers were being detoured off the Interstate at the Casa Blanca Exit 175.