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Client Name
Iowa DOT
Client Type
Services Provided
  • Acquisition Plats & Easements
  • Boundary & Retracement Surveys
  • Bridge Design
  • Preliminary DOT Surveys
  • Public Engagement & Meeting Facilitation
  • Topographic Survey & Subsurface Utility Engineering
Project Manager
Contact Wade Greiman, PE
Transportation Business Unit Leader

On-call Services for the Iowa DOT

As part of an on-call design contract, the Iowa Department of Transportation (DOT) asked Snyder & Associates to complete the final design for multiple construction contracts completed between 2014 and 2018 beginning south of the Iowa 92 Interchange to the west mixmaster in Des Moines. The work included:

  • Grading and paving near the Iowa 92 interchange
  • Paving near North River and Badger Creek including roadway design leading up to new northbound and southbound bridges on I-35 over the North River and Badger Creek.
  • Reconstruction of I-35 northbound lanes from the Polk/Warren County line to the I-80/235 systems interchange and the east half of the Grand Avenue Interchange.

Addressing Pavement Concerns & Other Roadway Issues

Initially constructed in 1958, the pavement on I-35 from the Highway 92 Interchange in Warren County to the I-80/235 interchange in Polk County was some of the oldest in Iowa and required ongoing maintenance. In addition to poor pavement conditions, specific areas to be addressed were:

  • Two interchanges in Warren County which had physical and geometric roadway deficiencies, along with one interchange in Polk County.
  • Functionally obsolete and structurally deficient bridges located throughout the corridor. This included overhead bridges at IA 92 and County Road G14 which didn’t meet current vertical clearance standards and had been struck several times.
  • Widening of I-35 from four lanes to six lanes to accommodate increased traffic throughout the corridor. Some areas will remain a four-lane facility, but can easily be expanded to six lanes as future traffic volume requires. Expansion to six lanes throughout the entire corridor is anticipated for 2032.

To quickly facilitate the final design, the initial preliminary design of northbound lanes completed by Iowa DOT design staff was compared with numerous changes made during years of construction with multiple construction contracts. Several modifications had to be made to the initial design to accommodate those changes. To maintain traffic on I-35, detailed staging and traffic control plans were required. In addition, 3D machine control files were developed and made available to contractors for Automated Machine Guidance (AMG), a process where construction equipment utilizes onboard computers and global positioning system (GPS) technology for horizontal and vertical guidance. Benefits of utilizing AMG include improved quality, safety for construction workers, and shorter construction timeframes.

Financial Planning for Roadway Projects

Prior to Snyder & Associates completing the final project design, the cost of all programmed projects was estimated at less than $100 million. However, because there were projects in the original environmental assessment that had not yet been programmed, that cost was expected to increase. Once all projects were added, the estimated cost exceeded $100 million. Because federal funds were being used for the project, a required financial plan was completed with guidance from the Federal Highway Administration (FHWA).

The purpose of a financial plan is to ensure financial resources for large projects are identified, available, and properly managed during the life of the project. It’s a comprehensive document designed to reflect the project scope, schedule, cost, and funding that goes far beyond the typical cost estimates prepared by engineers. Progress is tracked over time through annual updates to the initial financial plan. Each annual update reviews and tracks actual dollars spent for each project and anticipated changes to overall project costs over the past fiscal year to determine if changes to project programming are needed.

All projects receiving federal funds with an estimated cost over $100 million and less than $500 million are required to have a financial plan reviewed by the FHWA. For projects that exceed $500 million, a financial plan that has been reviewed and approved by the FHWA is required.

While it’s typically only done for large, complex projects, this type of detailed financial planning strategy is useful for smaller projects as well. Although the financial plan for a small project will be less complicated, it is equally important to track all aspects of the project cost, changes that occur, and anticipated funding sources. In the event a funding shortfall, Snyder & Associates can assist with the identification of potential funding assistance sources and the preparation of required applications.

Snyder & Associates completed both the final roadway design and financial plan for the reconstruction of Interstate 35. The majority of the project is slated for completion following a final paving project near Bevington, Iowa in 2017.