Highway 101 to See Overnight Lane Closures This Week Near Wellsona Road in San Luis Obispo County

Drivers traveling along Highway 101 in San Luis Obispo County should expect to see overnight lane closures this week as crews continue to work on safety improvements near Wellsona Road. 

The California Department of Transportation’s (Caltrans) is currently building an undercrossing and frontage road near the intersection of US 101 and Wellsona Road, which will result in alternating lane closures in both directions of the highway. 

As a result of the ongoing work, overnight lane closure and traffic switch will be in effect on Tuesday, Wednesday, and Thursday (April 7, 8, and 9, 2026) from 6 p.m. to 7 a.m., Caltrans shared in an update on their website. 

One lane will be open in both directions. 

The closure will allow crews to remove temporary barriers and install permanent delineation. 

Access to Wellsona Road from US 101 will stay unchanged, according to Caltrans. Direct access to the western section of Wellsona Road will be available for southbound drivers and can be accessed via a detour for northbound motorists. 

The eastern section of Wellsona Road will be accessible via a detour for southbound drivers and directly accessible via a right turn lane for northbound drivers. 

Motorists have been advised to drive slowly and carefully in the work zones. 

Wellsona Road Safety Improvement Project

The construction and lane closures are part of Caltrans’s Wellsona Road Safety Improvement Project. The project’s primary aim is to reduce the severity and number of collisions at the intersection of Highway 101 and Wellsona Road in San Luis Obispo County. 

Over the years, this intersection has been experiencing several broadside and left-turn merge-related collisions. According to Caltrans, the intersection has been the site of 16 collisions, including 14 multi-vehicle and three fatal crashes, in the past five years.  

The intersection is the second-most fatal crossroad in San Luis Obispo County in terms of the number of fatalities over the past 10 years, according to The Tribune.  

Based on the analysis of accident figures, the rate of collisions at this site is higher than the statewide average, according to Caltrans.  

Under the project, Caltrans will build a new undercrossing below US 101, south of the existing intersection, to remove the need for drivers to make left turns across traffic on US 101. 

A 112-foot-long bridge will be constructed, along with a frontage road to connect the undercrossing with Wellsona Road on either side of US 101. 

The contractor for the $12.2 million project is CalPortland Construction of Santa Maria. 

The project is expected to be completed later this month. 

Although work was projected to be completed in March, work on this project was delayed due to prolonged wet weather conditions during the Christmas and New Year holiday season, according to The Tribune.