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SR 539, Ten Mile Road to Badger Road Widening - Mock Roundabout

Trucks, Buses, Farmers Drive Future Guide Meridian Roundabout
August 10, 2006


Do not drive beside trucks in roundabout

Oversize truck enters roundabout and passes through easily and safely.
Grader drives through roundabout
Truck and trailer drive through roundabout


The proof was in the gravel Thursday as WSDOT traffic engineers meticulously
built a full scale roundabout in a gravel parking lot in Lynden.  The two lane roundabout was a replica of the four roundabouts that we will build along the Guide Meridian in 2008.  We built the roundabout to give drivers of semi trucks, fire and rescue, buses and farm equipment the chance to drive a full size roundabout. 

Survey crews marked the dimensions and then maintenance personnel assisted in painting the lane markings and adding the signs that would be in place on the real roundabouts.

Though some were skeptical at first, responses were mostly positive after driving through the roundabout and taking turns at several locations. One bus held several Lynden Christian School bus drivers that took turns driving the course. Truckers brought their longest trucks and farmers showed up with their biggest farm equipment to give it a try.

Traffic engineers boarded each vehicle and talked with drivers as they ran the course to give them directions and advice, as well as to solicit their views. Traffic engineer Phil Rust was one of the engineers that climbed aboard buses and semi’s all day and felt that letting drivers get a hands-on feel for the size and shape made the mock roundabout a worth while project.

“You could see it in their faces. Once they had run the course a couple times it was obvious they were comfortable with it,” said Rust. “We can claim roundabouts work all day long, but we'll never be as credible as those who drove the roundabout today.  People will believe drivers' testimonials from today.”

Two projects will widen nearly 11 miles of SR 539 from two to four lanes to increase safety, improve freight movement, and relieve congestion. Four roundabouts will be constructed during the second project.

Driving roundabouts with trucks
  1. As you approach a roundabout, there will be a yield sign. Take both lanes before reaching the yield sign. This may be necessary to make a right turn, and helps to prevent cars from entering next to you.
  2. As you enter, yield to circulating traffic on the left, but you don’t need to stop if the way is clear. Feel free to use the raised area around the center island, it’s called a truck apron and is designed to support large trucks.
  3. Stay to the right of the center island and hug the outside of the circle. Your trailer may ride up on the truck apron but that’s exactly what it’s designed for.
  4. As you exit the roundabout you may need to drive on the truck apron again to keep your trailer from riding up on the exit curb.
Tractor and trailer drives roundabout School bus drives roundabout
Truck drives roundabout Truck and pup drives roundabout
Long truck drives roundabout Long bed truck drives roundabout
Truck drives through roundabout Public transit bus drives roundabout
Tractor with trailer drives roundabout Long truck drives roundabout
 Snow plow drives roundabout