The sequence began abruptly before dawn. Commuters traveling inbound encountered sudden deceleration near milepost 257. According to preliminary radio dispatches from the Arizona Department of Public Safety, a dark-colored crossover struck a disabled passenger car resting partially in the left travel lane. The force of that primary impact pushed the disabled car across the center lanes into the path of an oncoming tractor-trailer carrying non-hazardous freight.
Tucson Fire Department units arrived within six minutes of the initial call. Crews faced heavy front-end damage across three passenger vehicles, with two drivers trapped inside their compartments. Specialized rescue teams deployed hydraulic cutters to peel back crushed vehicle roofs while paramedics established a stabilization staging area directly on the freeway asphalt.
Pima County emergency medical services deployed four advanced life-support ambulances to the scene. Paramedics rushed three injured individuals to Banner-University Medical Center with trauma-level injuries, two listed in critical condition. DPS officers cordoned off the left and center lanes immediately, soon opting for a complete westbound closure as debris and fuel slicks spread across all four main travel lanes.
