WSDOT conducted a pre-design study of US 101 in Sequim between the Simdars Road Interchange and Palo Alto Road. As part of the study, a public online open house was held Jan. 27 to Feb. 10 and the summary (PDF 1.3MB) describes the feedback WSDOT received.
Some common concerns about roundabouts on highways were expressed during the public open house
Crashes will increase with roundabouts on highways
Roundabouts at intersections are designed to be safer for all users and have fewer conflict points. Also, roundabouts at intersections on two-lane rural highways show overall crashes are reduced by up to 68 percent and a reduction of injury crashes is 88 percent.
Drivers won't slow down for roundabouts on US 101
High-speed approaches to roundabouts include advance signing, pavement markings and raised channelization. With proper design, drivers are directed to adjust their speeds, slow on approach and navigate the roundabout safely.
Why not build a traffic signal instead of a roundabout
Improvements like stop signs and signals, while very familiar, aren't always the safest choice. With intersections representing about one-quarter of annual U.S. traffic fatalities and roughly half of all injury crashes, safer designs are needed that improve mobility while saving lives.
Roundabouts on high-speed highways
Studies by Kansas State University measured traffic flow at intersections before and after conversion to roundabouts. In each case, installing a roundabout led to a 20 percent reduction in delays during peak hours. There are many roundabouts currently on Washington State highways with speeds of 50 MPH and greater. These modern roundabout designs account for high-speed approaches by providing longer splitter islands and pavement markings, along with enhanced signing. Some of these roundabouts that currently exist on two-lane high-speed highways include two on SR 3 in Mason and Kitsap counties, SR 12 in Lewis County, SR 510 in Thurston County and there are two located on SR 395 in eastern Washington. There are a number of roundabouts on highways that are being planned for the future.
Explore our site and learn more about roundabouts.
The Washington State Legislature allocated funding for this study through the Washington State Motor Vehicle Account. A total of $200,000 has been allocated for the pre-design study.
The final study report is available for viewing online. Two alternatives were recommended at the outcome of the pre-design study.
1. Build a new US 101 westbound on-ramp and eastbound off-ramp to Simdars Road with a single lane roundabout at the East Washington Street intersection.
2. Build a new two-lane frontage road from Palo Alto Road to Simdars Road.
The published study report outlines the pre-design process, potential alternatives that were considered, data analysis, local community outreach, and the final recommendations for improving system performance on US 101 between the Simdars Road Interchange and Palo Alto Road.
