Frequently Asked Questions - Bridge and Roadway Design

The project connects with Routes 25 and 31, both of which are State Routes and important highways.

There are no plans to design or build a facility with four-lane capacity.

The bridge is designed to accommodate the traffic that is projected for the year 2030. The traffic studies indicate that this will require a two lane bridge. Once built, the project will be a link within a network of two lane roads. It would not be practical to place a short section of a four-lane facility within a network of two-lane roads. These two factors warrant a two lane facility.

The bridge piers that must be built in the river will be designed and constructed to minimize the impacts to the flow characteristics of the river and impacts to the river ecosystems. There will be some construction activities that will be performed in the river in order to build the bridge. These construction activities will be controlled and performed in ways that will minimize the release of sediment into the river.

Altering the channel depth or shape in the area around the bridge would change the flow characteristics of the river. Dredging the channel could slow the flow of the river at this location and could have environmental impacts to the river ecosystem. There is no plan to dredge the channel.

The bridge type study is not yet complete and several profiles for the bridge are still being considered. The relationship between the height of the bridge above the water and the cost of the project is being evaluated to select the most cost effective structure.

Just north of the proposed location the river becomes too shallow for large motorized watercraft such as the St. Charles Belle paddle wheel river boats; however, the river is suitable for canoes and smaller boats at this location. As stated above, the piers will be spaced about 150 feet apart. The clearance will be a minimum of 12 feet over normal water level. This design follows the standards for bridge design as directed by the Illinois Department of Transportation and would allow current boating uses to continue.

Yes, the river is about 500 feet wide at the bridge location. The bridge must span the river and also 500 feet over the floodplain on the east bank. The bridge type study has not been completed, but the piers will likely be spaced about 150 feet apart. This will require three piers in the river and another four piers over the floodplain.