The proposed Illiana Tollway, which garnered federal approval in December, is facing a legal challenge from local environmental groups.
The Environmental Law and Policy Center filed the lawsuit in federal court Thursday on behalf of Openlands, Midewin Heritage Association and the Sierra Club.
The complaint alleges that the Federal Highway Administration, Illinois Department of Transportation and Indiana Department of Transportation "relied upon inflated population, employment and traffic forecasts in order to determine that the proposed Illiana Tollway was necessary," according to the Environmental Law and Policy Center.
It further claims that officials failed to consider the proposed tollway's potential negative impact on the environment, including on the Midewin National Tallgrass Prairie.
Those against the proposed expressway call it a boondoggle that will cost taxpayers money and farmland, while adversely affecting those who live near the designated area for the would-be tollway.
In January, Illinois Gov. Bruce Rauner issued an executive order putting a stop to progress on the public-private partnership until a cost-benefit analysis is done on the proposed 47-mile tollway, which would connect Illinois' I-55 to Indiana's I-65.