State Route 1 study finds localized congestion hotspots, recommends targeted fixes to preserve corridor character

A consultant team commissioned by Mendocino County updated the travel demand model for State Route 1 and identified localized congestion and safety priorities, while recommending targeted, context‑sensitive mitigations rather than wholesale widening of the scenic coastal corridor.

TJKM lead Sandeep Raju explained the study updated a 2008 model to a 2024 base year, collected summer peak counts (including July 4 data), and calibrated the model using 2020 Census and local plan inputs. The team tested multiple built‑out scenarios (25, 50, 75 and 100 percent build‑out) and 2030/2035 horizons to understand how future residential and employment growth would affect corridor operations.

Consultants found the majority of evaluated intersections would continue to operate at acceptable levels under the tested scenarios, but they identified four intersections and one roadway segment that were either operating at unacceptable levels today or close to capacity in 2035. The report flagged two locations in the Fort Bragg area as particularly close to capacity and recommended further study, including signal‑warrant analyses and consideration of roundabouts or other low‑cost geometry and speed interventions at collision‑prone locations. "State Route 1 is the major north south coastal route and it supports residents, emergency access and tourism," Raju said.

The team also produced VMT forecasts and reported overall growth in residential VMT of approximately 1.47 times 2024 levels by 2035 under the scenarios evaluated. Consultants said they incorporated external/through trips using statewide travel model inputs and calibrated local feeder‑road flows using newly collected intersection counts. The analysis highlights collision patterns (a 10‑year collision database showed many rear‑end and fixed‑object crashes) and suggests speed‑management and intersection geometry improvements where appropriate.

Commissioners and staff emphasized the need to frame recommendations so Caltrans (which manages State Route 1) can pursue low‑cost, context‑sensitive options rather than large‑scale signalization or widening that would alter the corridor’s scenic character. The consultants said the report can inform the Local Coastal Program update and provide a transportation basis for future land‑use decisions and mitigation requirements.

The commission did not take action on the study; staff and consultants will incorporate feedback and the model will be available to evaluate future project impacts and mitigation strategies.