The State Route 156 West Corridor Project is a comprehensive effort to improve safety, mobility, and freight efficiency along State Route 156 in northern Monterey County. This corridor is a critical east-west route connecting State Route 1 and US 101, serving as a major artery for agricultural freight, tourism, and local commuters. The project is divided into three segments:

Segment 1: Castroville Boulevard Interchange

The State Route 156 / Castroville Boulevard Interchange is the first phase of the corridor project. This segment will replace the existing signalized intersection at State Route 156 and Castroville Boulevard with a grade-separated interchange.

Key Features: 

  • Three modern roundabouts

  • One mile of Class I bike/multiuse path

  • Americans with Disabilities Act (ADA)-compliant pedestrian refuge islands and crosswalks

  • Improved connectivity to the Castroville bike/pedestrian bridge

  • Enhanced access to North Monterey County High School and affordable housing developments

The project is fully funded and scheduled to begin construction in Fall 2026.

Project Benefits

Improves safety at a high-collision location 
Reduces congestion and greenhouse gas emissions 
Enhances freight reliability and access to US 101 
Connects affordable housing, schools, and jobs 
Supports tourism and economic development 

Segment 2: SR 156 Expressway Conversion

Segment 2 is envisioned to convert State Route 156 into a four-lane expressway between Castroville Boulevard and US 101. 

This includes:

  • Transitioning the existing State Route 156 into a frontage road for local circulation

  • Adding bike lanes and multimodal infrastructure

  • Improving traffic flow and safety for freight and passenger vehicles

Segment 3: US 101/SR 156 Interchange Reconstruction

Segment 3 involves a complete redesign of the US 101/State Route 156 interchange, including:

  • A direct flyover connection from eastbound State Route 156 to northbound US 101

  • A modified partial-cloverleaf interchange

  • A new frontage road system to improve local access and circulation