Environmental groups have written to the Federal Highway Administration asking the agency to rescind its December 2014 approval for the Illiana Expressway.
The groups claim new developments and revelations, including Gov. Bruce Rauner's refusal to offer any statement of support, undercuts previous rationales for the road.
"A lot of changes have taken place, but No. 1 is what we have known all along and that's that the financial plans for the road have never looked promising," said Erica Dodt, a conservation organizer with the Sierra Club.
The letter was written and submitted April 10 by the Sierra Club, Midewin Heritage Association, Openlands, and the Environmental Law & Policy Center.
In December 2014, the Federal Highway Administration issued its Record of Decision approving plans for the road. It was a key victory for supporters of the 47-mile toll road that would link Interstate 65 in Indiana and Interstate 55 in Illinois.
That approval came despite the environmental groups filing an earlier court challenge in July 2013 to a previous Federal Highway Administration decision on the road. At that time the groups claimed the federal agency violated the law by approving an environmental study that failed to adequately assess potential impacts to endangered wildlife, critical habitat and other sensitive areas.
During the past year, support for the road has waned on a number of fronts and opponents have picked up new ammunition in their fight to keep it from ever being built. That shift culminated in an executive order from Rauner in January halting planning and development of major interstate construction projects including the Illiana Expressway pending a review.
The letter from the environmental groups also cites a March 20 letter from the U.S. Forest Service to the Federal Highway Administration stating it had erred in a previous evaluation when it said the road would only have minimal environmental impacts on the Midewin Tallgrass Prairie.
The U.S. Forest Service letter said the service believes the Illiana Expressway would in fact negatively impact the grassland's bird habitat and a full range of remedies would be needed to protect that habitat.