Princeton’s historic Red Covered Bridge will advance through critical engineering phases in 2026 as the Illinois Department of Transportation works toward repairing damage from a 2023 semi-truck collision.

The 149-foot landmark has been closed since November 2023, when a semitruck attempted to pass through the north end, damaging the bridge’s façade and roof. The IDOT has allocated approximately $1 million for repairs as part of its multi-year program.

While much engineering work remains to be completed, the scope of the necessary repairs to the 162-year-old structure was finalized and received approval from the State Historic Preservation Office on Dec. 8, IDOT said in a news release.

According to IDOT, the work involves a complete replacement of the roof, roof cross bracing, damaged roof cross bracing rods, floor beams and siding. In addition to the structural repairs, IDOT is planning several items to help preserve the historic structure for future generations, including replacing all the existing lighting and wiring and adding fire suppression piping and security cameras.

Other improvements include applying a fire-resistant coating on the interior of the structure, painting the exterior and making repairs and upgrades to the pump house.

The project completed Phase I engineering in 2025, which defined the scope of work and preliminary cost estimates. IDOT received approval from the State Historic Preservation Office in April that repair plans will not adversely affect the bridge’s historic character.

Phase II engineering is expected to begin once Phase I design approval is received from IDOT’s Region 2 engineer. This detailed phase will take 12-18 months to complete and will result in advertising a repair contract to bidders.

Currently, District 3 is wrapping up the first phase of engineering, which will define the scope of work and provide a preliminary cost estimate, IDOT said. Phase II, which includes the preparation of detailed construction plans, specifications and a cost estimate, resulting in advertising a repair contract to bidders, will begin soon and is anticipated to take less than a year to complete.

IDOT said that another aspect being considered is a vehicle height detection system at the approaches that would activate flashing lights to warn truck drivers before approaching the 10-foot, 11-inch-tall bridge. As well as additional signage on the roads approaching the Red Covered Bridge is proposed, as well as the replacement of all existing signs that warn drivers of the height restriction with new, high-visibility versions. Selected signs will be equipped with flashing beacons to attract additional attention.

All these improvements are hoped to deter future damage to the bridge on Bureau County Road 1950 E, just west of Illinois 26, 1 mile north of Princeton.

The bridge underwent a thorough structural inspection in 2024 to assess both collision damage and typical aging. IDOT took immediate precautions after the accident, including temporary roof support to prevent additional damage.

ExpandAutoplay

Image 1 of 6

A view of the Red Covered Bridge on Monday, June 30, 2025 in Princeton. Last Friday, the Illinois Department of Transportation announced that the historic bridge enters next rehabilitation phase. Phase II includes the preparation of a detailed cost estimate and expected to take 12 to 18 months to complete and will result in advertising a repair contract to bidders. Approximately $1 million is identified to pay for the needed repairs in IDOT’s most recent multiyear program. A view of the Red Covered Bridge on Monday, June 30, 2025 in Princeton. Last Friday, the Illinois Department of Transportation announced that the historic bridge enters next rehabilitation phase. Phase II includes the preparation of a detailed cost estimate and expected to take 12 to 18 months to complete and will result in advertising a repair contract to bidders. Approximately $1 million is identified to pay for the needed repairs in IDOT’s most recent multiyear program. The bridge survived a number of threats, both intentional and unintentional, including arson, erosion and high winds. It also has survived several strikes by large trucks with it's most recent strike in 2023. (Scott Anderson)