Illinois environmental groups have filed a lawsuit over the proposed Illiana Tollway. They claim federal approval relied on faulty information and didn't adequately consider environmental impacts.
The complaint was filed Thursday in U.S. District Court in Chicago on behalf of Openlands, the Midewin Heritage Association and the Sierra Club.
It claims the U.S. Department of Transportation, Federal Highway Administration and Illinois and Indiana officials relied on inflated population, job and traffic forecasts to justify the $1.5 billion, 47-mile link between northern Illinois and Indiana.
It also said reviewers failed to adequately consider potential harm to the Midewin National Tallgrass Prairie.
Critics said the public-private partnership will leave taxpayers on the hook if toll revenue falls short.
Illinois and Indiana have suspended work on the project pending a cost-benefit review.