As the Oregon Department of Transportation (ODOT) planned for a new roundabout on US 20 at Barclay Drive in Sisters, the freight industry expressed concern about whether large trucks would be able to navigate the roundabout safely and efficiently.

In order to address those concerns, ODOT recently staged a series of roundabout testing sessions in Redmond and Portland. The first took place at the Deschutes County Fairgrounds, where a variety of truck and trailer combinations were invited to negotiate a test roundabout. Kittelson & Associates, Inc. (Kittelson) conducted the testing.

The test roundabout was laid out using surveyed points to exactly replicate the proposed design. Traffic cones served as curbs and sandbags stood in for mountable truck aprons in the test roundabout. Each truck was equipped with a camera on the front and back, recording the vehicle’s ability to navigate the proposed roundabout. A car equipped with a dashcam and an aerial lift with a mounted camera were also used to record their progress from other angles. A video showing examples of the vehicles tested is available on YouTube.

Joel McCarroll, PE, PTOE, ODOT Region 4 Traffic Manager, supervised the testing and says he was satisfied to see that the loads operated the way he and others involved in the testing expected them to.

“We got a lot of positive feedback from the people who brought the trucks. One towing company owner voiced some specialized needs because he needs to be able to get these large-haul trucks back to his shop,” Joel says. “I look at it as additional public involvement.”

In addition, the tests will ensure ODOT will not have to make design corrections after construction, which is scheduled for the summer of 2016.

A second round of testing was done at Portland Meadows because many of the heavy freight companies are based in Portland and requested the tests to be done locally to save them the time and expense of sending trucks to Central Oregon.

ODOT and Washington County used the Portland Meadows testing opportunity to also test a roundabout being proposed for OR 47 near Forest Grove. That design is being developed by CH2M HILL with peer review by Kittelson. Testing both designs on the same day allowed efficiencies both for the agencies and the freight companies bringing vehicles to test.

The US 20 and OR 47 roundabouts will be the first to be added to the state highway system in more than a decade, and will be the second and third roundabouts on the state system.