A collision just south of Riggs Road in the southbound lanes of State Route 347 on Tuesday morning snarled traffic and sent one person to a hospital, the Department of Public Safety said.
The crash was caused by a medical episode, according to DPS spokesman Bart Graves.
At 8:38 a.m., a gray Nissan SUV driven by an elderly woman swerved into a semi-truck, Graves said. She was transported to a hospital, and her condition was not available.
SR 347 was reopened after nearly an hour.
State troopers were assisted by Gila River Police Department.