A portion of southbound Interstate 680 in the East Bay will be shut down this weekend as part of an ongoing repaving project. Here’s a breakdown of what to know and alternate routes if planning to travel through the area during the closure. What part of I-680 will be shut down during the weekend closure? Southbound I-680 will be closed between Alcosta Boulevard in San Ramon and I-580/I-680 connector in Pleasanton. Caltrans says all I-580/I-680 connectors will remain open through the right most lanes on southbound I-680. When will I-680 close? Crews will begin shutting down southbound I-680 at 9 p.m. Friday. When will I-680 reopen? Caltrans expects southbound I-680 to reopen by 4 a.m. Monday. Are there additional closures during the I-680 weekend shutdown? The far-left lane (Express Lane) and left shoulder will be closed on northbound I-680 between Amador Valley Boulevard in Dublin and Alcosta Blvd in San Ramon, according to Caltrans. Why is I-680 shutting down for the weekend? Caltrans said crews will replace a portion of the existing damaged roadway with new pavement. “The work will repair deteriorating existing pavement and enhance motorist safety while reducing the number of nightly closures needed on the project,” Caltrans said on its website. “This weekend closure will accomplish the amount of work that otherwise would require an estimated 40 nighttime closures.” Detours during I-680 weekend closure Here are the detours in place during this weekend’s closure on southbound I-680: Motorists driving west on Interstate 80 in Vacaville and Fairfield will remain on I-80 to southbound I-880. Motorists on southbound I-680 near the Benicia Bridge can take I-780 west to I-80 to southbound I-880. Motorists on southbound I-680 in Concord can take SR-4 to I-80 to southbound I-880 or SR-24 to I-80 to southbound I-880. Motorists on southbound I-680 in Walnut Creek can take SR-24 to I-80 to southbound I-880. Motorists on Southbound I-680 in Danville take westbound I-580 to SR-238 to southbound I-880 or eastbound I-580 to SR-84 to southbound I-680. Full Shutdown Locations: Saint Patrick Way on ramp onto southbound I-680 Maps of I-680 closures and detours Will there be more I-680 closures? Two additional partial weekend closures of southbound I-680 in the same area are planned for Oct. 4 through Oct. 7 and Oct. 18 through Oct. 21. Caltrans said these events will not be a full closure and motorists can travel on I-680 through the construction work zone. The planned partial closures may be rescheduled due to weather or other unanticipated developments. If that happens, Caltrans said it will update the public. For more information, visit Caltrans’ website. Caltrans Jul 1 Caltrans installs nearly 200 highway cameras across Bay Area taxes May 21 Gas tax alternative: Caltrans pilot program will charge drivers per mile