Joliet, IL

Houbolt Road Extension and Diverging Diamond Interchange (DDI)

Client: City of Joliet
Our Role: Design Engineer (DDI Conversion) & Independent Engineer (Houbolt Road Extension)

Two parallel highway bridges crossing over a roadway surrounded by grass and industrial buildings.

The City of Joliet faced mounting congestion and safety concerns along the Houbolt Road corridor, a vital connection between I-80 and U.S. Route 6. With a projected 20,000 daily truck trips and limited right-of-way, the existing infrastructure was no longer sufficient to handle the demands of one of the nation’s largest inland ports. The project’s goal was twofold:

Convert the outdated diamond interchange at I-80 into a modern Diverging Diamond Interchange (DDI) to improve traffic flow and safety.
Extend Houbolt Road southward with a new 2,000-foot toll bridge over the Des Plaines River, creating a direct freight connection between intermodal facilities and I-80.

This complex, $130 million project required innovative engineering solutions, public-private collaboration, and careful coordination with multiple agencies and stakeholders to ensure success.

Our team played a pivotal role in delivering both elements of this transformative project. As the design engineer for the DDI conversion, our firm led the Phase I and Phase II design services, including contract plan preparation, special provisions, cost estimates, and permit acquisition. This work ensured that the DDI would efficiently accommodate high-turning truck volumes while minimizing the need for major structural modifications.

For the Houbolt Road extension, our firm served as the independent engineer, providing key studies, cost estimates, and procurement documentation for the design-build process. We also oversaw construction to ensure compliance with project specifications and quality standards. Our contributions were instrumental in:

Innovative Project Delivery: The project leveraged a public-private partnership (P3)—a first-of-its-kind in Illinois—where private funding covered the toll bridge’s construction and long-term maintenance.
Design/Build Execution: Our team helped structure Illinois’ first major roadway project delivered via the design/build method, setting a precedent for future transportation projects in the state.
Technical Innovations: The DDI configuration was designed to fit within the footprint of the existing I-80 overpass, reducing construction costs and minimizing disruption. The Des Plaines River bridge was erected using advanced strand-jacking techniques, significantly reducing closures on this critical navigation channel.

Key Features

Diverging Diamond Interchange: The first DDI in Illinois where the cross street passes under the expressway, improving traffic flow and reducing congestion.
2,000-foot Des Plaines River Bridge: A key freight corridor addition that eliminates truck bottlenecks and improves regional connectivity.
Multi-Modal Considerations: A new multi-use path along the bridge and roadway enhances safety for pedestrians and cyclists.
Sustainability-Focused Design: Earthwork was balanced on-site, reducing material disposal, and innovative bridge deck forms minimized construction waste.

Outcomes

The Houbolt Road project is a game-changer for Will County’s freight network, ensuring continued economic growth while addressing community concerns about traffic congestion and safety.

Freight Efficiency: Truckers save up to 20 minutes per trip, reducing fuel costs and increasing reliability.
Public-Private Collaboration Success: A 99-year lease agreement ensures no public funding is required for bridge maintenance.
Improved Safety: The DDI reduces conflict points, enhancing safety for all road users.
Economic Impact: Improved access to the CenterPoint Intermodal Center, North America’s largest inland port, strengthens Illinois’ role in global trade.>

By combining innovative design, alternative project delivery, and strong public-private collaboration, this project has set a new benchmark for infrastructure development in Illinois. The Houbolt Road improvements will serve as a blueprint for future P3 and design-build transportation projects, ensuring that vital freight corridors can evolve to meet modern demands.

American Council of Engineering Companies – Illinois, 2024, ACEC_IL Honor Award for Transportation.
American Public Works Association (APWA) Chicago Metro Chapter, 2024, Southwest Branch Project of the Year – Transportation (Over $75 Million).