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Diamond Bar, CA (July 14, 2026) – A multi-vehicle collision left at least two people hurt on July 12 on the southbound State Route 57 near the Pathfinder Road off-ramp in Diamond Bar.
The crash was reported around 9:35 a.m. and involved a red Mazda, a silver Ford sport utility vehicle, a red Nissan, and at least one additional vehicle. Initial reports indicated that the silver SUV rolled over onto its roof, while the red Mazda also overturned, leaving both vehicles upright and blocking several travel lanes.
Witnesses told dispatchers that one driver appeared to be conscious but was unable to communicate the extent of their injuries. Emergency units arrived to assist those involved and manage traffic while tow trucks removed the damaged vehicles. By about 9:48 a.m., all vehicles had been moved to the right shoulder, allowing the roadway to reopen.
The severity of the reported injuries has not been released.
The cause of the collision remains under review as investigators continue gathering information.
Our thoughts are with everyone affected, and we wish those hurt a full and speedy recovery.
Why Vehicle Rollovers Can Increase the Risk of Injury
Rollover crashes are among the more serious types of roadway collisions because they expose vehicle occupants to multiple forces in a short period. Even when a vehicle lands back on its wheels, people inside may experience injuries that are not immediately obvious. Seat belt use, vehicle design, speed, and the direction of the rollover can all influence the outcome.
When several vehicles are involved, investigators typically examine physical evidence such as tire marks, vehicle damage, debris patterns, and witness accounts to determine how the sequence unfolded. Traffic camera footage or dash camera recordings may also help clarify the events leading up to the collision. Medical evaluations performed after a rollover are usually important because some injuries may not become apparent until hours after the crash.
