California Department of Transportation crews will close all eastbound lanes of State Route 78 near South Rancho Santa Fe Road in San Marcos for four consecutive nights this week as part of ongoing highway improvements.
The full closure will run from 10 p.m. to 5 a.m. Monday, October 19, through Thursday, October 22, while workers replace concrete slabs at a weigh-in-motion station. Drivers will exit at South Rancho Santa Fe Road and can re-enter the highway using the same road's on-ramp.
The work is part of a larger corridor upgrade spanning nearly 18 miles of SR-78, stretching from Interstate 5 in Oceanside to Broadway and Lincoln Parkway in Escondido. Officials say the project aims to preserve existing roadway infrastructure, enhance safety features, and modernize the corridor to meet current and future transportation demands.
The total project carries an estimated price tag of approximately $126 million, funded through the State Highway Operation and Protection Program. Federal funds account for $111.5 million of that total, including $9.2 million from infrastructure legislation, with the state contributing $14.5 million.
Caltrans officials said portable signs will alert motorists to the closures and suggest alternate routes. Nearby residents and businesses should expect construction noise and lighting during overnight work hours. Crews have scheduled the work at night using temporary closures to protect both workers and drivers, though increased traffic on detour routes is anticipated.