Study: Suisun Valley roads mostly adequate but southern segment could see weekend/harvest congestion

County planning staff on March 3 presented a traffic capacity analysis for Suisun Valley Road that found generally acceptable weekday performance but identified potential localized congestion during weekends and harvest season if proposed development proceeds without mitigation.

James Fusick, director of Resource Management, and assistant Matt Tuggle described the study area (Suisun Valley Road ‘spine’ divided into five segments). The consultant evaluated current operation (weekday peaks and harvest season) and modeled a 10‑year build-out using assumed mixes of wineries, tasting rooms, boutique hotels and agricultural uses. Existing-condition results showed most segments operating at level-of-service A–C under typical conditions; Segment A (Solano College to Rockville Road) carried the highest volumes and is most likely to experience Saturday and harvest-period queuing.

The study noted about 69 collisions in the corridor over five years, mostly property-damage-only, though 2022 saw a number of serious collisions. Staff said improvements are partially funded for southern Segment A (design underway with some construction funds identified through a Priority Conservation Area grant from MTC) and recommended prioritizing shoulder, sidewalk, transit stop and safety work; they also suggested operational interventions and further grant-seeking (Highway Safety Improvement Program, PCA). The county will monitor weekend and harvest peaks to determine whether additional measures or project acceleration are needed.

Supervisors asked about bike lanes, pedestrian safety, the college connector and potential route consolidation; staff said they will continue concepting, pursue funding, and coordinate with transit and city partners. No formal action was required; the report was informational and intended to guide future capital and operational priorities.