Night Full Closures and Day One-Way Traffic Control on State Route 84 (Niles Canyon) in Unincorporated Sunol

Schedule: Night full closures begin Thursday, September 25, 2025, at 8:00 PM. One-way traffic control begins Saturday, September 27, 2025, at 5:00 AM.

Alameda Cunty - Caltrans will implement full night closures (8p-5a) & one-way daytime traffic control (5a-8p) on State Route 84 (Niles Canyon) in Unincorporated Sunol near post mile 15.5, at the Rosewarnes Undercrossing (U/P) and the Niles Canyon Railway Brightside Yard. Work will include installing and connecting specially designed guardrails to the newly constructed bridge on eastbound State Route 84.

Caltrans will begin preparing for the installation of the one-way traffic controls and signal devices on Thursday night, September 25, 2025, from 8:00 PM to 5:00 AM, Friday morning.

Starting Friday night, September 26, 2025, at 8 PM, between Main Street and Palomares Road follow the below schedule:

• Daily hours (7 days a week) 5 AM-8 PM One-Way Traffic Control
• Nightly hours (7 days a week) 8 PM-5 AM Full Freeway Closure (Detour required)

This work is scheduled to be completed by 11/22/2025.

Traffic Impacts

• Motorists should expect significant delays, particularly during commute hours.
• Detour Options:
  • NB/SB I-680 to SR-238
  • SR-238 back to NB/SB I-680

Caltrans advises motorists to allow extra travel time and use alternate routes when possible. Caltrans appreciates the public's patience while this critical safety improvement work is completed.

For 24/7 traffic updates, please visit 511.org: https://x.com/511SFBay For real-time information, visit Caltrans QuickMap: https://quickmap.dot.ca.gov Follow us on X: https://x.com/CaltransD4 Or call 1-800-472-7623, 1-800-427-ROAD for state highway conditions statewide.