"How can that be in light of the reduction in miles driven? A combination of factors.
Roadways were already so badly saturated with traffic before the recent spikes in fuel prices that the decline in miles traveled hasn't significantly loosened the gridlock.
In addition, major construction projects, temporarily shutting down lanes on the Edens Expressway, the Stevenson Expressway and the Tri-State Tollway have effectively canceled out the gains from many vehicles being driven less.
For an average of 13 hours and 19 minutes each day, vehicle speeds are less than 50 m.p.h. on at least 20 percent of the Chicago-area highway system, according to the Urban Congestion Report compiled by the Federal Highway Administration."