A $12 billion capital plan that would create thousands of jobs seems like a panacea for the metropolitan region's woeful unemployment rate of 10.5 percent.
But predicting job creation numbers isn't an exact science, experts say regarding the Illinois State Toll Highway Authority's building program.
Tollway directors Thursday adopted a construction agenda for the next 15 years they say will create 120,000 permanent jobs and 13,000 temporary construction jobs.
This includes expectations of economic development from a new interchange at the Tri-State Tollway and I-57 plus building the Elgin-O'Hare Expressway extension east to the airport and a western bypass around O'Hare International Airport.
The tollway used Illinois Department of Transportation, Federal Highway Administration and Associated General Contractors of America models, among others, when crunching the numbers, officials said.
While projecting construction jobs is fairly straightforward, permanent jobs -- some of which are based on expectations of economic development -- are a different animal, University of Illinois at Urbana-Champaign economist Fred Giertz said.
Overall, it's best to take such job projections with a grain of salt because "almost every estimate is exaggerated for political reasons," Giertz noted. "The multipliers are wildly optimistic."
Northwestern University civil and environmental engineering professor Joseph Schofer noted that when it comes to forecasting jobs "there's a fair amount of uncertainty associated with it. It depends on the state of the economy and the context."
New activity on the west side of O'Hare could detract from established commerce on the east side in Rosemont, Giertz noted.
"You never know how much is being rearranged as opposed to being created," he said.
Also, there's question of whether drivers paying more tolls will spend less on other things, putting a damper on economic growth, Giertz said.
The tollway also relied on projections from an advisory group studying the Elgin-O'Hare Expressway extension and western bypass around O'Hare, which are key components of the capital plan.
The study notes that 19,000 of the jobs are directly connected to the construction of a western terminal at O'Hare, a project the city of Chicago has shelved.
Tollway Chair Paula Wolff said the agency relied on time-tested, reliable formulas when calculating the numbers. But she noted, "they are models and there are many variables we can't anticipate today. These have always been estimates."