SR-84 Nightly Closures For Bridge Replacement

Caltrans began overnight full closures on State Route 84 in Sunol on May 18 as construction started on the Arroyo de la Laguna Bridge replacement project. The closures affect Niles Canyon Road between Main Street and Bond Street on Monday through Friday nights, according to a Caltrans advisory published May 18. The agency said the shutdowns will run from 8 p.m. to 5 a.m. for about four weeks. Daytime work will continue in the same area through October, Caltrans said. ### Which stretch of SR-84 is closing each night? State Route 84 is closing between Main Street and Bond Street in Sunol during the overnight work window, Caltrans said. The agency also described the closure area as SR-84 between Main Street and Pleasanton-Sunol Road and said traffic will be detoured around the work zone while crews are on site. (dot.ca.gov) Monday-through-Friday closures are scheduled overnight rather than during the day. Caltrans said all work is weather dependent and advised motorists to allow extra travel time or use alternate routes when possible. ### Why is Caltrans replacing this bridge now? The Arroyo de la Laguna Bridge was built in 1939, Caltrans said. (dot.ca.gov) The agency said the replacement is intended to provide a safer and more dependable connection along SR-84 and to bring the crossing up to current design and safety standards. Structural inspections completed in October 2013 found scour at piers 4 and 5, according to the project page. (dot.ca.gov) Caltrans said the bridge is classified as “scour critical,” meaning pier foundations are rated as unstable because stream flows have washed away supporting material, and the Office of Earthquake Engineering Analysis and Research identified the bridge in 2016 as seismically vulnerable and a candidate for retrofit. ### What will drivers use instead of the canyon route? Caltrans posted detours for several directions of travel, including routes using Main Street, Kilkare Road, Foothill Road, Castlewood Drive, Pleasanton-Sunol Road, Sunol Boulevard and Interstate 680. Drivers heading toward Fremont during the closure are directed to take the connector to I-680, merge right, exit at Mission Boulevard and continue on Mission Boulevard, according to the advisory. (dot.ca.gov) Motorists coming from Livermore toward Sunol are being routed to I-680 and then to Sunol Boulevard, Castlewood Drive and Foothill Road, Caltrans said. The agency said changeable message signs will be activated to guide drivers through the detours. ### What is Caltrans building in place of the old span? (dot.ca.gov) Caltrans said the project will replace Bridge No. 33-0043 at post mile 17.2 in unincorporated Alameda County. The agency’s project page says the new bridge is planned as a 310-foot-long, 64-foot-wide structure with one through lane in each direction, wider shoulders that can accommodate bicycle lanes, a pedestrian path on the south side and standard-height barriers. (dot.ca.gov) The new crossing is also intended to widen the roadway and add Americans with Disabilities Act-compliant sidewalks, according to the May 18 construction notice. Caltrans said the work is starting with Stage 1 construction on the north side of the bridge. ### How long will this phase last, and what comes after? (dot.ca.gov) Caltrans said the overnight full closures that began May 18 are expected to last about four weeks. The agency said daytime construction will continue through October and that additional traffic advisories will be issued as the project progresses. (dot.ca.gov) October is the next concrete milestone Caltrans has identified for this phase of work. Drivers can track updated closure notices and project information through Caltrans District 4’s advisories and the Arroyo de la Laguna Bridge project page. (dot.ca.gov)