Santa Barbara to Mussel Shoals Home

Widening Projects

SBCAG and Caltrans have undertaken widening 16 miles of Highway 101, known as Highway 101: Santa Barbara to Mussel Shoals, to add carpool lanes and address a narrow portion of Highway 101 that currently has two lanes in each direction. The project is phased as depicted on the Project Location Map below. Phases I and 2 are complete. Construction on Phase 3 is nearly complete, and Phase 4 construction is underway.

Carpinteria to Santa Barbara

Design, Environmental Review


  • Hwy 101 widening (10.9 miles)
  • Carpool lanes added
  • Cabrillo Blvd Interchange
  • Sheffield Dr Interchange
  • Rehabilitate existing lanes
  • Sound Walls
  • Creek Bridges

Approximately $700 million
*forecasted construction costs


Measure A, state & federal gas taxes

Click on the maps below to view or print segments of Phase 4.

Phase 4A Carpinteria

Highway 101: Carpinteria added a peak-period carpool lane to the freeway in each direction within the City of Carpinteria. The new lanes tie into recently added third lanes to the south and upcoming projects to the north. New bridges were built over Franklin and Santa Monica Creeks. There is new freeway on- and off-ramp improvements at Santa Monica Road, Carpinteria Avenue, and Reynolds Avenue. Six new sound walls are constructed to reduce freeway noise for neighbors. On local streets, improvements to the intersections at Santa Monica Road & Via Real, Reynolds & Carpinteria Avenues, and Bailard Avenue & the freeway ramps are complete.

Phase 4B Padaro

Highway 101: Padaro will widen Highway 101 to 3 lanes in each direction between the City of Carpinteria and Summerland. The project includes new bridges over Toro and Arroyo Parida Creeks. At the South Padaro Lane Undercrossing, the bridge and on- and off-ramps will be replaced. At the North Padaro Lane Interchange, new on- and off-ramp improvements will be built. There are also three new sound walls.

Phase 4C Summerland

Highway 101: Summerland will widen Highway 101 to 3 lanes in each direction between Sheffield Drive and North Padaro Lane. At the Evans Avenue Undercrossing, a new bridge will connect the existing freeway bridges and be accompanied by pedestrian, bike lane, and lighting improvements. At the Sheffield Drive Interchange, new freeway bridges will be built along with new righthand on- and off-ramps on southbound Highway 101 and improved northbound on- and off-ramps. The on-ramp at Wallace Avenue will be replaced. Two sound walls will be built.

Phase 4D Montecito

Highway 101: Montecito will add a new peak-period carpool lane in each direction from the Romero Creek Bridge north to Olive Mill Road along with new on- and offramps. The project includes new bridges over Romero, San Ysidro, and Oak Creeks.

Advanced Work (2023)

The project team is advancing a $50 million portion of the Montecito segment (pending local permitting) based on a reprogramming of state transportation funds. Construction is scheduled to begin in spring 2023.

Phase 4E Santa Barbara

Highway 101: Santa Barbara will add a new peak-period carpool lane in each direction from Olive Mill Road to Sycamore Creek. The Cabrillo Boulevard Interchange will be reconstructed with new bridges and right-hand freeway ramps, including a new northbound off-ramp and new southbound on-ramp. There are two new proposed sound walls.