US 101/Hearn Avenue Regional Multimodal Interchange

Project Scope

This is a rendering of the project on an aerial image. It shows the project limits from roughly Corby Avenue crossing US 101 to Santa Rosa Avenue, the southbound US 101 off-ramp to where it intersects with Corby Avenue, and the section of Corby Avenue from that intersection to Hearn Avenue. The rendering shows the increased width that will include additional travel lanes, raised median, sidewalks and bikeways, and provides a cross section view of the roadway with these improvements. The rendering also shows how the project will connect to the SMART multi-use path to the west and proposed ADA elements at the intersections within the project limits.The US 101 Hearn Avenue Regional Multi-modal Interchange Project (project) will demolish and reconstruct the Hearn Avenue interchange overcrossing in the same location to increase vertical clearance over United States Highway (US) 101, widen the overcrossing to provide two vehicle lanes in each direction, a median, sidewalks, and Class II and Class IV bikeways that will extend to Corby Avenue and Santa Rosa Avenue. The project will also widen the southbound US 101 off-ramp with turning lanes at its intersection with Corby Avenue, add lanes at the intersections of Hearn Avenue/Corby Avenue and Hearn Avenue/Santa Rosa Avenue, and add pedestrian curb ramps and crosswalks that meet the requirements of the American Disability Act and incorporate protected intersection facilities for bike crossings and detection to reduce potential conflicts between bikes and vehicles. The project is the final phase of the Hearn Avenue and Santa Rosa Avenue Complete Streets Project to provide roadway widening, pedestrian, and bicycle improvements intended to improve mobility in southern Santa Rosa.

Project Purpose

The purpose of this project is to relieve traffic congestion and improve regional traffic operations, including providing multimodal access and connectivity adjacent to the Highway 101 and Hearn Avenue intersection.

Project Need:

  • Existing Hearn Avenue overcrossing is one lane in each direction with no shoulders
  • Insufficient capacity for vehicles leads to queuing back onto the mainline southbound US 101 auxiliary lane during peak periods
  • Congestion and lack of shoulders delays emergency response times
  • No sidewalk on the north side and discontinuous sidewalk on the south side
  • No bike facilities on Hearn Ave overcrossing
  • Nonstandard vertical clearance over US 101
  • Non-crashworthy bridge railings

Project Benefits:

  • Improve local traffic circulation and regional traffic operations (resulting in improved first responder access and response time)
  • Improve multimodal access, connectivity, and operations
  • Improves access to essential goods, services and jobs
  • Improves access to recreation
  • Improves access to schools and adult educational and career development
  • Improves access to public transit and transit travel times
  • Improve overall safety of the facility


Construction work is expected to start in Spring of 2024.

Current Advisories

Caltrans to Implement Clearing on Hearn Ave. Overcrossing Bridge In Santa Rosa to Expedite the U.S. 101 and Hearn Ave. Interchange Project

Work starts 7:00 AM, Wednesday, January17

As part of the U.S. 101 and Hearn Avenue Interchange Project, Caltrans will clear vegetation in the construction zone along the Hearn Avenue overcrossing between Corby Avenue and Santa Rosa Avenue starting on January 17, 2024.

The work will occur along the north and south side of Hearn Avenue overcrossing. A temporary staging area in the far-right eastbound traffic lane on the Hearn Avenue overcrossing is required to accomplish this work.

Until further notice and for the next few weeks, motorists traveling on the Hearn Avenue overcrossing above U.S. 101 heading eastbound towards Santa Rosa Ave. during the clearing work will need to merge into the far-left traffic lane.

Motorists should expect delays, slow down in the construction zone and watch for construction signs, crews and equipment.

The clearing is part of a larger project to replace the U.S. 101 and Hearn Avenue Interchange between Corby Avenue and Santa Rosa Avenue in Santa Rosa.

Project Contact

For more information, contact Caltrans Sonoma County Public Information Officer Jeffrey Weiss.