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DIAMOND BAR, Los Angeles County, Calif., Oct. 30, 2026 — A multi-vehicle crash shut down the connector from southbound State Route 57 to westbound State Route 60 on Thursday morning, October 29, according to the California Highway Patrol. At least one person was hurt, and the transition road was closed for an extended period while crews cleared the scene.
The crash was reported shortly after 10:20 a.m. on the SB 57 to WB 60 transition road near Diamond Bar. Initial radio traffic described a black SUV facing the wrong way after colliding with a white SUV and another vehicle, and a separate report described a white car and a black SUV blocking lanes. The number of vehicles involved was not fully confirmed in early reports, though dispatchers referenced both a two-vehicle collision and a three-vehicle collision at the same location.
Airbags deployed in at least one vehicle, and one occupant reportedly had trouble getting out. A child was reported inside one of the vehicles. The Los Angeles County Fire Department responded to the scene. The extent of injuries beyond the one confirmed injured occupant was not released.
CHP units closed the transition road entirely to clear wreckage, and a tow rotation truck capable of carrying two SUVs was called in to remove vehicles from the area. A SigAlert was requested around 11 a.m., with CHP estimating the closure could last 35 to 40 minutes for the transition road, and the agency later confirmed the roadway had been cleared by late morning.
The cause of the crash had not been determined as of publication. The CHP has not said whether speed, impairment, or another factor contributed to the collision.
We hope everyone who was hurt makes a full and speedy recovery.
More on Crashes in Diamond Bar, CA
This multi-vehicle crash happened on State Route 57 in Diamond Bar, CA. We cover crashes across Los Angeles County as they're reported, and you can browse the latest in our Los Angeles County accident reports.
Frequently Asked Questions
Why does following distance matter so much in highway traffic?
Keeping a safe gap gives drivers more time to react if a vehicle ahead slows or stops suddenly, which can prevent a chain-reaction collision, especially on interchanges and transition roads where traffic merges and slows.
Do crashes like this one tend to cause additional collisions nearby?
Yes. Once a crash blocks lanes, traffic backs up quickly, and following vehicles that don't adjust speed in time can strike stopped cars, which is why responders usually work to close or reroute traffic fast.
Why are multi-vehicle crashes harder to investigate than single-car wrecks?
With several vehicles involved, investigators have to reconstruct the order of impacts, determine which vehicle struck which, and sort through conflicting witness accounts, which usually takes longer than in a single-vehicle crash.
What typically causes pile-ups involving three or more vehicles?
Common factors include sudden braking, lane changes in heavy traffic, reduced visibility, and vehicles following too closely, though any specific cause depends on what investigators determine in each case.
