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ACTT Workshop: Iowa/Illinois
I-74 Corridor Study - Bridging the Future

Chapter 2: Project Details

2.1. Project Overview

The Iowa and Illinois DOTs have proposed improvements to the I-74 corridor in the Quad Cities from Avenue of the Cities in Moline, Illinois, to 53rd Street in Davenport, Iowa. The study corridor traverses the Cities of Moline, Bettendorf and Davenport and includes a crossing of the Mississippi River (See Figure 1). The proposed improvements comprise additional capacity on I-74; an improved Mississippi River crossing; enhancements to the existing six service interchanges; upgrades to the connecting arterial roadway system; and improved opportunities for transit, bike/pedestrian and intermodal connections.

Figure 1: Project Area

Map showing the proposed improvements to the I-74 corridor in the Quad Cities from Avenue of the Cities in Moline, Illinois, to 53rd Street in Davenport, Iowa. The corridor study extends north, from its starting point, a third of the way from the bottom of the map and centered left to right where I-74 begins its northward run through Moline. The project ends in Davenport, Iowa, due north of where it began and just south of the 1-74/I-80 interchange. The I-74/I-80 interchange is shown at the top of the image with Davenport extending westward and Bettendorf just to the east. Rock Island and north/south running Route 67 complete the left side of the map, with East Moline to the northeast and Coal Valley to the south. The Mississippi river runs southwest through East Moline and Rock Island, taking a WNW turn as it passes under I-74 and cuts its way through Moline at the center of the map.

The study corridor contains a mix of residential, commercial and industrial development throughout most of its length. While there are residential areas throughout the project corridor, there are concentrations of residential property south of the commercial area in Moline and north of the business area in Bettendorf. Newer residences have sprung up adjacent to the I-74 corridor in Davenport near the northern end of the project corridor.

The key industrial areas are located along the river in both Moline and Bettendorf. In addition, two trails (the Great River Trail in Illinois and the Bettendorf Riverfront Trail in Iowa), numerous parks and various open-space areas are located along the river in both States and along Duck Creek in Bettendorf and Davenport.

2.2. Project History and Development

I-74 plays an important role in the local, regional and national transportation network. The I-74 corridor was opened to traffic in the early 1970s, which means that both the Interstate pavement and the bridges within the study area are more than 30 years old. The Iowa-bound bridge over the Mississippi River was built in 1935 and is now 70 years old.

Since its opening, the I-74 corridor has served as a critical link in the Quad Cities regional transportation network, functioning as the principal commuter route for Iowa and Illinois residents traversing the Mississippi River. The corridor is strategically located to provide connections to regional rail, air, river and intermodal transportation hubs.

The need for improvements to I-74 was first identified in the December 1998 "Quad Cities Mississippi River Crossing Major Investment Study," an analysis spearheaded by the Iowa and Illinois DOTs. As a result, in early 2000, the DOTs initiated planning and environmental studies for the I-74 corridor. These analyses not only validated the need for improvements to I-74, but they also evaluated a full range of alternatives and identified anticipated environmental consequences.

Public input has proven to be a key component of the planning and environmental studies, with two public information meetings held during phase one of the study. The purpose of the first meeting, held in July 2001, was to: 1) present information regarding current I-74 conditions and the purpose and need for proposed improvements; and 2) obtain public comment on concept alternatives developed in the early stages of the study. At the second meeting, held in August 2002, the DOTs presented information regarding current I-74 conditions, the purpose and need for the proposed improvements, the continued use options for the existing bridges and the status of project development issues. Both meetings were conducted using an open-house format.

Once public comments were compiled, the DEIS was prepared and then signed in October 2003. At the public hearing for the DEIS in December 2003, the DOTs presented the findings of the corridor study, the DEIS and the draft 4(f) statement. Information presented at the hearing included a summary of the alternatives considered and the alternatives still under consideration as well as a discussion of the potential adverse and beneficial effects of the alternatives. Nearly 400 people attended the hearing.

Work accomplished in 2004 included updating traffic forecasts and analyses for the year 2035, investigating design options for trail crossings over the Mississippi River, investigating navigational requirements along the Mississippi River, and conducting additional traffic analyses in downtown Moline, downtown Bettendorf and near the 53rd Street interchange. As a result, the stakeholders were able to identify a preferred alternative in January 2005. Because the project is in the study phase, no cost estimates are in place. Major construction efforts (the bridge and bridge approaches) will not likely begin before the year 2010.

2.3. Project Purpose

The purpose of the proposed improvements is to: 1) improve capacity, travel reliability and safety along I-74 between Avenue of the Cities in Moline and 53rd Street in Davenport, and 2) provide continuity with local land use planning goals. The need for the proposed improvements is based on a combination of factors considered key to providing better transportation service and sustaining economic development. In particular, the Iowa and Illinois DOTs are focused on addressing the following needs:

  • Traffic demand and service.
  • Roadway geometry.
  • Economic development.
  • Dependability of travel.
  • Transportation connections.
  • Infrastructure condition.
  • Safety considerations.

Steadily increasing traffic volumes and decreasing LOS throughout the project corridor are a concern for both the Iowa and Illinois DOTs. In 2000, I-74 carried 74,000 vehicles per day near the river; by 2002, that number had increased to 77,800. Near the river crossing, the I-74 mainline operated at LOS E during the peak hour in 2000. It continues to maintain LOS E but is just above the threshold for LOS F. This is far below the minimum acceptable LOS of C. Motorists in this area regularly encounter stop-and-go conditions and backups at interchange ramps. As traffic volumes continue to increase, these conditions will only worsen.

Roadway elements that contribute to safety concerns throughout the corridor include: 1) narrow lanes and a lack of shoulders on the existing river-crossing structures and approaches; 2) a series of reverse curves with tight radii on the Illinois approach to the river bridge; 3) maximum vertical grades on both the Illinois and Iowa approaches; 4) close interchange spacing; and 5) short, steep taper rates on the ramps. In addition, the roadway itself is deteriorating to the point that major reconstruction or rehabilitation may be necessary at the same time the project corridor is undergoing the improvements being discussed in the I-74 corridor study.

2.4. Project Challenges

The key design challenges are as follows:

River Crossing Locations.

Demand for access across the river is expected to increase 5 percent by 2025. Five highway bridges currently provide access across the Mississippi River in the Quad Cities. Of those, only three cross within the more densely developed portions of the Quad Cities and are used predominantly by area commuters. Because of its location and characteristics, the I-74 bridge carries the majority of daily crossings: approximately 90 percent of traffic on the I-74 bridge originates from or terminates in the local metropolitan area.

Downtown Access.

Given the economic importance of Moline's and Bettendorf's downtown areas and the limited availability of viable alternative river-crossing routes, it is important to maintain access to these downtown areas during construction.

Roadway Geometry.

The I-74 project will upgrade the roadway geometrics to current design standards and improve safety by adding shoulders to the Mississippi River crossing, increasing ramp taper rates, eliminating reverse curves on the Illinois approach and increasing interchange spacing, all while maintaining traffic across the river.


Having an economic and efficient design that has the support of the community will be vital in moving towards construction. SAFETEA-LU earmarks are being used for the preliminary engineering and environmental work, with additional earmarks in place for final design and right-of-way.


This project involves multiple States, Counties and Cities. Effective communication and coordination will be key to moving this project forward.

2.5. Project Status

During the next 18 to 24 months, the project team will continue to refine the design features of the preferred alternative to the level required to support delineation of a selected alternative, prepare the FEIS and complete the ROD. Preliminary roadway design will begin for a large portion of the corridor, including the new I-74 Mississippi River Bridge. With this work, the project team will refine the design features for the I-74 mainline, ramps and connecting roadways. This will enable the team to analyze potential environmental impacts, identify ROW requirements, and develop a more precise estimate of the construction timeframe and budget.

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Updated: 10/27/2015
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