Project Team Recommends Diverging Diamond Design for I-5 Aurora/Donald Interchange

During the June 11 Aurora City Council meeting, Oregon Department of Transportation (ODOT) Project Manager Anna Henson and others gave an update on the I-5 Aurora/Donald Interchange project.

They had previously attended the council’s April meeting, when councilors were presented with two alternatives that were being considered for the interchange.

One was a single point interchange, similar in style to the Market Street interchange in Salem. The freeway ramps come to a single signal in the middle of the interchange under such a design.

The second was a diverging diamond. It’s a new interchange type for the Portland area, although there is one in Southern Oregon in Phoenix.   

Councilors were informed June 11 that a project team from ODOT, Marion County and other entities recommended the diverging diamond interchange. That team used 30 criteria to pick between the two designs.

The diverging diamond design reduces the number of traffic conflicts and increases safety. It is also more free-flowing than other interchange design styles.

Survey and field work and traffic modeling has been conducted and preliminary design is the next phase. The design work will be around 30 percent completed by December. An interchange area management plan will be done concurrently.

Marion County and the Oregon Transportation Commission will have to approve the project prior to construction in the spring of 2022. It is currently on schedule.

Under the design, Bents Road would be relocated to a new intersection to the west. Dolores Way would be relocated to the east.

The team has engaged multiple stakeholders as part of the process to gather their input to inform ODOT’s decision.

For more information, view the attached documents below from the June 11 presentation to the city council.