UPDATED 03/22/11 11:28 a.m.

CHICAGO (CBS) — Every day, Chicagoans depend on bridges, overpasses and underpasses that are half a century old or more.

But a new report released Tuesday says many of them pose a serious safety hazard to drivers, if action isn’t taken soon.

As CBS 2’s Susanna Song reports, the report by Transportation for America says more than 2,000 Illinois bridges, or about 8 percent of the total, are structurally deficient.

For one example, the group says the overpass that carries Western Avenue over the intersection with Belmont and Clybourn avenues is severely deteriorated.

LISTEN: Newsradio 780’s Bernie Tafoya reports

The wear on the overpass is visible to the naked eye. Under the overpass, rust and corrosion are visible where the support columns meet the deck, and while above, rebar is exposed where concrete has cracked and crumbled.

The overpass was built in 1960 to provide easy access to the Riverview amusement park, which has been gone for more than 40 years. Outgoing Ald. Eugene Schulter (47th) has said he would like to see the overpass demolished, but officials say there is just not enough money to do it.

“When the state of Illinois is spending almost half of its available transportation dollars on new transportation projects, instead of fixing crumbling bridges like this, we have a problem with priorities,” said Kevin Brubaker of the Environmental Law and Policy Center as he stood alongside the Western Avenue overpass. “We also have a problem with not enough dollars available. The federal gas tax hasn’t been raised in more than two decades.”

Another problem bridge is the broad concrete Kennedy Expressway overpass at Ashland Avenue and Cortland Street. The concrete support columns are crumbling, and on some of them, rebar is exposed like ribs on a dry skeleton.

Transportation for America is made up of members of the Metropolitan Planning Council, the Illinois Chamber of Commerce, and city aldermen. They say the crumbling bridges are a public safety issue, and they are urging Congress to pass a transportation bill where more money is added for fixing roads and bridge, and also giving more power to the local government to decide where the dollars go.

Northwestern University civil engineering professor Joseph Schofer told CBS 2’s Kristyn Hartman Monday that the problem may not be as severe as it looks.

“As bad as it looks in terms of structural integrity, it may not be a huge problem,” Schofer said.

He says a hands-on inspection is what you need to find trouble, and those inspections have found just that.

Schofer said there is not enough money geared toward maintenance, but he also said the inspection program in place is “pretty reliable.” Inspectors are obligated to pull a bridge out of service if it presents a danger to the public.

But Transportation for America wants to take no chances. It was the Illinois Highway Authority that deemed 2,000 bridges across the state “structurally deficient,” and such problems can have consequences.

Most infamous was the I-35W Mississippi River bridge collapse in Minneapolis on Aug. 1, 2007. Thirteen people were killed and 145 were injured when the bridge suddenly collapsed during the evening rush.

Standing near the Western Avenue overpass, Kathleen Woodruff of Transportation for America said worries about a similar collapse are not unfounded.

“The bridge in Minneapolis that we all remember crumbling – it was structurally deficient, and only really denoted as that months before it collapsed, so we’re running a risk,” she said. “It’s a safety issue.”

When asked if Illinois drivers are at risk, officials said, “Let’s hope not.”