Arcata’s U.S. 101-Sunset interchange project pushed to summer start

The U.S. 101-Sunset Avenue interchange rebuild is now expected to break ground next summer, pushing back Arcata’s long-promised fix for one of the city’s most awkward traffic patterns but keeping the project alive. The redesign is meant to replace three stop-controlled intersections with two roundabouts, a change officials say will improve traffic flow, bicycle and pedestrian safety, and the gateway into central Arcata and Cal Poly Humboldt.

For commuters, the delay means the daily grind on Sunset Avenue, LK Wood Boulevard and the northbound U.S. 101 ramps will continue a little longer. Once construction begins, the corridor near the campus, the highway and western Arcata is expected to see changing access patterns, lane shifts and altered traffic rhythms that will be felt by drivers, bicyclists and pedestrians moving between Cal Poly Humboldt and the rest of the city.

The project has been moving through planning for years. The City of Arcata’s timeline lists preliminary design in 2023, final design in 2024-25, funding for construction in 2024-25, an open house in September 2025 and construction planning in 2025-26. The California Transportation Commission’s 2024 STIP materials also listed the U.S. 101 and Sunset Avenue Interchange Project at $1.4 million for PS&E and right-of-way work in fiscal year 2024-25, underscoring that the work has been advancing even as the start date slipped.

The overhaul gained a major boost on January 8, 2025, when Rep. Jared Huffman announced a $15 million U.S. Department of Transportation RAISE grant. That package was described as covering two roundabouts, pedestrian and bicycle access, new bus stops, signs, lighting, ADA improvements and connections to the nearby trail system. Arcata Mayor Alex Stillman called the project overdue, saying, “Fifty years later sunset will receive the improvements it needs.”

The corridor matters because it is not just a freeway interchange. The project area sits beside Cal Poly Humboldt and within walking distance of Arcata High School, Arcata Elementary School, the Arcata Skateboard Park, Shay Park and Larson Park, making it one of the city’s most heavily used multimodal gateways. A 2017 Central Arcata Areawide Traffic Study recommended roundabouts in the Sunset and LK Wood area to address congestion and delays, and transportation advocates have continued pressing the city to preserve separate pedestrian and bicycle facilities and eliminate slip lanes. The basic design is set; the wait for construction is what has changed.