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SR 20 – Discovery Road & Kearney Street Intersection Roundabouts Pre-Design Study – Get to know the project

What’s it all about?

The existing signal systems on SR 20 at the Mill Road (Discovery Road) and Kearney Street intersections in Port Townsend have reached the end of their useful life. They require frequent and extensive maintenance to keep them operational, and the signal heads are suspended on span wire instead of the preferred mast arms. WSDOT has proposed replacing the outdated signals at both locations with compact roundabouts that fit within the intersection footprint for improved mobility, safety, and reduced maintenance costs to taxpayers year after year.

What will the improvements look like?

We plan to construct compact roundabouts on SR 20 at the Mill Road (Discovery Road) and Kearney Street intersections beginning spring of 2023. Compact roundabouts are smaller than a standard roundabout, feature mountable curbing, a traversable center island and shorter and traversable splitter islands.

Aerial view of a compact roundabout on SR at Mill Road (Discovery Road)

The proposed pavement markings act as a proven traffic calming measure to reduce vehicle speeds and guide traffic down to a single lane approaching the intersection. The two red triangle splitter islands along SR 20 are 3 inches tall and mountable. The red triangle splitter island at Mill Road is 1 inch tall and mountable by trucks as needed. The white plastic candles/curbing protects the bicyclists from traffic.

Center island close-up view of a compact roundabout on 20 at Mill Road (Discovery Road)

The compact roundabout’s center island is fully mountable by larger vehicles and features gray left-turn truck alignment guides. This design feature means that freight haulers and oversized loads can navigate the intersection effectively with the new roundabout proposal. Trucks turning left onto SR 20 from Mill Road would follow the gray guides on the center island.

Aerial view of a compact roundabout on SR 20 at Mill Road (Discovery Road)

The dark red stamped concrete area on both sides of the Mill Road intersection provide additional space to help facilitate semi-trucks turning movements. The power pole at the Mill Road intersection on the right of the image could be relocated to give freight haulers additional turning movement space.

Aerial view of a compact roundabout on SR 20 at Kearney Street

The double yellow line striping slows and funnels traffic down to a single lane approaching the intersection. The design proposal includes a transit location in front of the local mini mart near the intersection. Transit buses, like freight haulers, will be easily able to navigate the compact roundabout.

Aerial view of a compact roundabout on SR 20 at Kearney Street looking south

The design proposal includes accommodations for those who walk or roll. White plastic candles/curbing to protect bicyclists from vehicle traffic.

Aerial view of the green bicycle lane featured near the compact roundabout on SR 20 at Kearney Street

In its current proposal, WSDOT was able to expand the existing green bike lane along SR 20 in front of the mini mart for bicyclists, so they can continue to have a continuous flow of traffic while using the roundabout.

Why roundabouts?

  • Improved safety
  • Reduced traffic delay
  • Reduced maintenance costs
  • No replacement needed
  • Works during power outages
  • Cost competitive

Studies show that roundabouts are safer than traditional traffic signals or stop sign-controlled intersections. They accommodate vehicles of various sizes, including emergency vehicles, buses, bicycles, semi-trucks with trailers, and farm and logging equipment, while improving pedestrian access. Roundabouts reduced injury crashes by nearly 75 percent at intersections where stop signs or signals were previously used for traffic control, according to a study by the Insurance Institute for Highway Safety (IIHS).

Timeline

  • Community outreach  –  fall 2020
  • Project design  –  spring 2021
  • Construction begins  – spring 2023
  • Construction complete  – summer 2024

For more information

Dennis Engel, WSDOT Olympic Region Multimodal Planning Manager

Debbie Clemen, WSDOT Olympic Region Multimodal Planning, SR 20 Project Lead