Major Collision Causes Traffic Delays on SR 57

Traffic Collision on State Route 57 in Diamond Bar Causes Delays Today

📍 Diamond Bar, CA

📅 Published: September 20, 2025 at 08:52 AM

🔄 Updated: September 20, 2025 at 10:04 AM

Map showing the location of the accident in Diamond Bar, CA
Diamond Bar, September 20, 2025 -

A traffic collision involving four vehicles occurred today on State Route 57 South near South Brea Canyon Road in Diamond Bar, CA. The incident took place during the busy morning commute, involving a motorcycle, a red sedan, and two additional unidentified vehicles.

Emergency services quickly responded to the scene to manage traffic and ensure safety. Initially, the High-Occupancy Vehicle (HOV) lanes were closed, leading to significant delays and congestion for motorists in the area. Debris was reported on the roadway, which further complicated traffic flow.

As emergency personnel worked to clear the scene, traffic was held in the affected lanes, causing backups that impacted many drivers. By approximately 9:37 AM, all lanes were reopened, allowing traffic to resume normal operations. However, residual congestion may linger as drivers navigate the area.

The California Highway Patrol was present to oversee the situation and facilitate the safe clearing of the roadway. Motorists are advised to remain cautious and aware of ongoing traffic conditions. This incident highlights the importance of safe driving practices, especially during peak travel times. For the latest updates on traffic conditions, drivers should check local traffic reports.

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