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Diamond Bar, CA (July 30, 2026) – A two-semi-truck collision caused major lane closures on July 29 along eastbound State Route 60 just west of Phillips Ranch Road in Diamond Bar.
According to police reports, the crash was reported shortly after 2:00 a.m. when two semi-trucks became involved, initially blocking the slow lane. One trailer detached from its tractor, leaving the two right lanes obstructed. The driver of one of the trucks was reported to be bleeding, prompting emergency units to assist.
Responding crews worked to clear the roadway. A SigAlert was issued after three of the four eastbound lanes were closed for several hours.
The cause of the collision remains under investigation as more information becomes available.
We hope the injured driver makes a full and speedy recovery.
Why Do Semi-Truck Crashes Usually Require Extended Highway Closures?
Crashes involving large commercial trucks frequently take longer to clear than those involving smaller vehicles. A fully loaded trailer can weigh tens of thousands of pounds, making recovery more complex when equipment becomes damaged or separated. Specialized heavy-duty tow trucks and rotators are often needed to lift or reposition large vehicles safely.
Fuel, oil, or cargo spilled onto the roadway can also require extensive cleanup before travel lanes can reopen. Crews may inspect the pavement for damage and remove debris to reduce the risk of additional traffic problems. As a result, lane closures on major highways can remain in place for several hours, especially during overnight recovery operations involving multiple commercial vehicles.
