Caltrans will shut down all westbound lanes of State Route 78 at South Rancho Santa Fe Road in San Marcos for four consecutive nights next week as part of ongoing highway improvements. The closures will run from 10 p.m. to 5 a.m. Monday, October 12, through Thursday, October 15.
Crews will use the overnight closures to replace concrete slabs at the weigh-in-motion station. Drivers will be redirected off the highway at the South Rancho Santa Fe Road exit and can rejoin westbound SR-78 using the same street's entrance ramp.
The work is part of the larger SR-78 Stewardship Project, a $126 million effort to upgrade a 17.7-mile stretch of the highway between Interstate 5 in Oceanside and Broadway and Lincoln Parkway in Escondido. Project goals include preserving existing infrastructure, improving safety, and modernizing the corridor to meet current and future transportation demands.
Funding for the stewardship project comes entirely from the State Highway Operation and Protection Program, with $111.5 million in federal dollars—including $9.2 million from the Infrastructure Investment and Jobs Act—and $14.5 million in state funds.
Portable signs will be posted along the route to alert drivers to the closure and suggest alternate routes. Nearby residents and businesses should expect construction noise and lighting during overnight hours, including backup alarms required by federal occupational safety regulations. Caltrans officials said crews will work to minimize disturbance to surrounding communities.
The agency cautioned that work schedules may change due to weather, traffic incidents, or other construction-related factors. Motorists are urged to stay alert in work zones and watch for workers and heavy equipment.