The final phase of the Highway 101 widening project is set to begin construction April 6 as the current phase nears completion.

The next phase of construction, Santa Barbara North, is the final segment of the Santa Barbara portion of the project.

Crews have added new lanes, ramps, and other improvements to the highway during the widening project. Construction on the final segment is set to begin in the spring.

The status of the project was presented to the Santa Barbara County Association of Governments on Thursday.

Fred Luna, director of Project Delivery & Construction, called the start of the final phase of the highway project a “huge milestone.”

The Santa Barbara part of the project was split into two portions. It spanned 11 miles between Carpinteria and Santa Barbara.

The Highway 101 project was originally split into multiple phases to allow local governments to pay for construction as work progressed, rather than in a single lump sum.

The total cost of the project is an estimated $700 million. It is partially funded by Measure A. SBCAG announced last year that it secured $134 million in funding for the last portion of the project.

The last segment will add a carpool lane between Hermosillo Road and Salinas Street. Crews will build a new interchange and two bridges at Cabrillo Boulevard and a new southbound on-ramp near Los Patos Way. 

Construction will also include a new teardrop roundabout near Cabrillo Boulevard and next to the northbound ramps near the Montecito Country Club along Old Coast Highway. 

Other improvements will include reconstructed lanes to improve visibility, updated ramps, drainage, lighting and signage.

The Los Patos southbound off-ramp will be permanently closed. The exit, which passes under a railroad bridge, was recommended for closure in November due to safety concerns.

Santa Barbara County First District Supervisor Roy Lee asked if the Los Patos exit could remain open in response to a public speaker who asked if the board could save the exit.

The speaker, who owns a business at the Post in Montecito, said businesses located near the off-ramp could lose customers.

Luna explained that the ramp is a non-standard exit and the distance from the road to the railroad bridge is 12 feet rather than the standard 16 feet. Trucks have hit the bridge in the past.

“Improvements couldn’t be made to that (exit) to keep it to standard,” Luna explained.

Luna also confirmed that the northbound and southbound off-ramps at Cabrillo Boulevard will be closed until 2028.

The southern phase of the Santa Barbara segment is set to finish construction by the end of 2026. This portion of the project included improvements to the highway between Hot Springs Road and Olive Mill Road.

Improvements to the area included new carpool lanes, sound walls for residents, safety barriers and new ramps. Roundabouts were also built at San Ysidro Road, Olive Mill Road, and Los Patos Way to Cabrillo Boulevard.

Luna said the final traffic shift on the southern portion of the project will happen in late May. The segment was narrowed to two lanes during construction to provide crews with space to work.

“That’s really our last major milestone on this segment of construction,” Luna said. The remaining work will be done in the median, he added.