I-39/90 & WIS 11/Avalon Road Interchange


2019 Engineering Excellence Award | State Finalist

Entering Firm: AECOM Technical Services Inc.
Client: Wisconsin Department of Transportation
Category: Transportation

The WIS 11 interchange between Janesville and Beloit is substantially more essential than a state highway in rural Wisconsin might seem. The highway is at the heart of many farming operations and is designated as a primary route in the Oversize/Overweight (OSOW) Freight Network. It was in dire need of reconstruction and presented a host of unique design challenges.

The close teamwork of AECOM Technical Services and subconsultant Strand Associates delivered a unique solution with a diverging diamond interchange (DDI). This is the first of its kind in Wisconsin and was necessary because of the OSOW requirements. A DDI has long sweeping curves for turns which accommodate OSOW vehicles. It also reduces crossing points which improve safety and overall traffic flow. This specific interchange has customized curve design to integrate effectively with the surrounding roads. The design also decreased the footprint of the bridge which saved money and time. Because the interchange is the first in the state, the design team embarked on an aggressive public outreach campaign to educate people on how to use the design. An animated instructional video helped with digital outreach and at public meetings.

Additional diverging diamond interchanges are now being implemented in Wisconsin using the experiences of this project. The design team reached for a novel solution that met the needs of the interchange and preserved major OSOW access and meets the needs of all travelers.

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