URBANA — Construction of an all-new interchange at Interstates 57 and 74 in northwest Champaign could cost as much as $135 million and require at least 37 more acres of right of way, according to alternatives offered by engineering firms working for the Illinois Department of Transportation.
Five alternative plans for the interchange were offered Wednesday at an IDOT-sponsored open house at the Champaign County Highway Department building.
Each of the preliminary engineering ideas for the interchanges features stacks of sweeping ramps, some as tall as 60 feet, rather than the cloverleaf design that has been used at the interchange for nearly 50 years. Similar multi-layer interchange designs are in place in downstate Illinois at East St. Louis, Effingham and Mount Vernon, said Joseph Crowe, deputy director of IDOT.
Motorists would be able to drive the ramps at 50 mph rather than the 25 to 30 mph speed limits now at the interchange.
But the beginning of construction of the expensive project is at least six years away, admitted Crowe.
"Right now all we're doing is this study," said Crowe. "That is called Phase 1 engineering where we look at the type of interchange, the environmental impacts for all the alternatives, the cost estimates, all those sorts of things.
"There is no funding at the present time for design, which is something a contractor would do a bid off of, or any kind of construction or right of way or utility adjustments if those are needed. None of that is funded at this time."
Actual construction costs for the each of the five alternatives range from $95 million to $125 million. But land acquisition costs are estimated at an additional $3 million to $7 million and utility relocation costs could be an additional $2 million to $3 million.
Each of the alternatives would require more land, from as little as 37 acres to as much as 106. At least one alternative shows ramps built where buildings are located today.
With the five alternatives, Crowe said, IDOT now will take public comment and go through a state and federal review process for environmental and cultural impacts. The final plan is the result of consensus-building, he said.
"It's a pretty involved process," he said. "That's why this is not design, this is planning."
In 12 to 15 months, Crowe said, the five alternatives will be narrowed to one. If funding is established, he said, design work could take another 18 to 24 months. After that, land acquisition and utility adjustment could take another year or two.
Local officials have been pushing for reconstruction of the interchange after a number of accidents in recent years.
But Priscilla Tobias, IDOT's safety engineer, said Wednesday the existing interchange is not among the worst in the state.
"We actually did a statewide curve analysis," she said. "Some of the (existing) ramps fall within the area where we need to see what we can do as far as safety improvements. None of the ramps on that interchange fall within the top 10 (for severe crashes). The bulk of the bad ramps are in the Chicago area and in Madison and St. Clair counties."
The worst ramp was ranked 15th in the state, she said.
"That analysis is what prompted the district to move forward with the enhanced vehicle-actuated signs that will go out there and the premium, high-friction surface treatment that will go on all the ramps," Tobias said.
The five planning options presented Wednesday came from Marion-based Bacon Farmer Workman Engineering and Testing and Springfield-based Crawford Murphy & Tilly Inc.
Here is the IDOT memo with the design alternatives.
Here is a look at the safety of the I-74 interchanges in Champaign-Urbana.