Westbound lanes of State Route 78 will be fully closed near South Rancho Santa Fe Road in San Marcos for four consecutive nights this week as crews replace concrete slabs used for weighing vehicles in motion, according to the California Department of Transportation.
The closures are scheduled from 10 p.m. to 5 a.m. beginning Monday, October 12, and continuing through Thursday, October 15. Drivers will exit at South Rancho Santa Fe Road and can merge back onto the westbound highway using the same road's onramp.
The overnight work is part of a broader asset management initiative covering nearly 18 miles of the highway between Interstate 5 in Oceanside and Broadway and Lincoln Parkway in Escondido. Transportation officials say the project aims to preserve existing roads, boost safety measures, and update the corridor to handle current and anticipated traffic demands.
The overall project carries a price tag of $126 million, with federal funding accounting for $111.5 million of the total and state funds contributing $14.5 million. Digital message boards will alert drivers to the closures and suggest alternative routes.
Residents and businesses in the vicinity should prepare for construction noise, lighting, and heavier traffic on detour roads during the nighttime hours. Caltrans cautioned that the schedule could shift due to weather, traffic incidents, or other unforeseen circumstances.