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 currently in construction, Phase 4, is depicted on the Project Location Maps below.

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

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

Phase 4B

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

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 and 4E

Highway 101: Montecito & Santa Barbara will widen Highway 101 to 3 lanes in each direction between Sycamore Creek in the City of Santa Barbara up to Romero Creek in Montecito (west of Sheffield Drive). Included are the reconstruction of the Hwy 101 bridges over Cabrillo Boulevard and a new southbound on-ramp (replacing the lefthand ramp removed in Phase 1). Bridges will be replaced at Montecito, San Ysidro, Oak, and Romero Creeks. Four new sound walls are included, and this design phase is also proposing to integrate some operational and safety improvements on Highway 101 and the ramps.