MINNEAPOLIS - In the days and weeks following the horrific, rush-hour collapse of the I-35W highway bridge a year ago, national and local politicians promised critical repairs would be made immediately to the nation's most problematic bridges.

But that talk has not totally translated into action.

In fact, an Associated Press review of data for the 20 most heavily-traveled, structurally deficient bridges in each state shows there's been very limited progress toward meeting that goal.

Just a bit more than one in 10 of the 1,020 problem bridges analyzed had their structural defects fixed - usually through a major rehabilitation or outright replacement.

But nearly two of every three of the busiest problem bridges in each state - carrying nearly 40 million vehicles a day - have had no work beyond regular maintenance, the AP found.

The remaining 24 percent have seen a partial improvement.

"At some point, relying on miracles is not going to be the best way to manage our system," said Pete Rahn, the transportation commissioner of Missouri. "I would pray we don't have to have another disaster to bring about the right attention to this. I see very little political will there."

Based on interviews with transportation officials, the most common approach has been to simply plan for repairs rather than fix problems now.

The bridges reviewed by the AP are not in imminent danger of collapse, state engineers and highway officials say. But the officials acknowledge the structures need improvement, many sooner rather than later.

The collapse of the eight-lane Interstate 35W bridge into the Mississippi River on Aug. 1, 2007, killed 13 people and brought widespread calls for repairs to bridges across the nation.

The AP gathered information on repair status from 48 states and Washington, D.C. In six states, data could not be obtained for some locally owned bridges. Louisiana and Nevada failed to respond.

The worst states were Indiana, Oklahoma, New Hampshire and South Carolina, where work was conducted on only one of each state's 20 most heavily traveled structurally deficient bridges.

The failure to follow through was not because of lack of effort, officials said. The cited soaring construction costs, budget shortages, election-year politics, a backlog of bridge projects, competing highway repairs and bureaucracy.

"The Minneapolis incident obviously caused people to stand up and take notice, but I think it got dwarfed by the bad economic news," said Pennsylvania Gov. Ed Rendell.

Rendell has joined a national campaign to demand more federal investment in infrastructure. But as Congress debates highway spending, some members criticize states for not devoting enough highway money to bridges. Also, the Bush administration has promised to veto the latest $1 billion proposed increase, itself a fraction of the estimated $140 billion needed for repairs on bridges alone.

"Thirteen people were killed and not much happened," said engineer William Schutt, a critic of the status quo of bridge assessment and repair. "Who's to blame? Congress, the American people - for putting up with it."

Bridges deemed structurally deficient have elements that need monitoring and parts that need to be scheduled for repair or replacement. The designation does not necessarily mean a bridge is unsafe.

"Structural deficiency ultimately determines whether a bridge will stand or fall," said Kris Kolluri, New Jersey's transportation commissioner.

"If you look at the full picture of bridges and the task that transportation professionals have," Kolluri said, "it's an overwhelming task."

A Federal Highway Administration inventory of data submitted by states lists about 70,000 structurally deficient bridges nationwide.

The Minneapolis bridge, one of the busiest in Minnesota, collapsed during a Wednesday evening rush hour into a tangle of steel, concrete and crushed cars. In addition to the 13 killed, 145 people were injured.

Investigators have yet to issue their final determination on the cause of the Minneapolis collapse but have said an error in the original design was the critical factor. Certain gussets - steel plates that fastened the trusses together - were roughly half the 1-inch (2.5-cm) thickness they should have been, investigators said.

The disaster has generated a rush of emergency bridge inspections, an extra $1 billion from Congress for bridge repairs so far and vows from leaders to tackle the problems.

Washington state Gov. Chris Gregoire promised to tackle two overdue bridge projects. But the Alaskan Way Viaduct along Seattle's waterfront won't be demolished until 2012, and work to replace the SR 520 floating bridge over Lake Washington will only begin that same year.

In all, 17 states proposed ambitious bridge and road spending totaling $13.7 billion. To date, $8.3 billion has won approval in six states, including $160 million in Maine, $600 million in Missouri and $6.6 billion in Minnesota.

But in 33 states and Washington, D.C., there was no significant new spending, and little debate.

Understandably, Minnesota's response has been among the most vigorous.

Lawmakers overrode Republican Gov. Tim Pawlenty's veto of the $6.6 billion transportation spending plan, which raised the gas tax, local sales taxes and vehicle registration fees. The Senate then sacked his transportation commissioner.

In June, a new commissioner outlined a $2.5 billion draft bridge improvement plan that would replace 11 major spans over the next decade using the new money. By 2018, 120 bridges that lack structural redundancies - like the doomed I-35W bridge - or that rank poorly on the structural sufficiency scale would be repaired, replaced or under construction.

Minnesota officials abruptly closed or partially closed three busy bridges after those inspections found flaws. The state also moved swiftly to replace the I-35W bridge. Contractors aim to complete work by Sept. 15 - 100 days ahead of the deadline.

Missouri was another bright spot, where the Legislature moved ahead on a stalled bridge-improvement plan.

Politics dashed ambitious plans in Colorado and Virginia. Colorado lawmakers killed proposals to raise car registration fees, sales and gas taxes. In Virginia, the governor's $1 billion transportation plan became a political, partisan showdown and wound up a stalemate.

The debate echoes from statehouses to Washington.

Last week, the U.S. House overwhelmingly approved another $1 billion for bridge work, though the White House has opposed the increase and has promised a veto.

The nation's bridges depend significantly on the federal government. In 2004, $10.5 billion was invested across the country on bridge improvements, according to the FHWA. The federal Highway Bridge Program provided $5.1 billion, with another $1.5 billion coming from other federal aid; states and local government paid $3.9 billion.

Much of the federal support comes out of the Highway Trust Fund, which is financed largely through fuel taxes - but high pump prices now have led people to drive less.

"The federal government has basically ignored infrastructure at every level," said Rendell, who, with California Gov. Arnold Schwarzenegger and New York Mayor Michael Bloomberg, has launched a group called Building America's Future to demand infrastructure investment. "They've just literally abdicated their responsibility."

According to the American Association of State Highway and Transportation Officials, a projected $14 billion shortfall means only about $27 billion in federal money will be available next year to states and local governments for new highway and bridge investments - a 34 percent reduction - even though the current federal highway act calls for spending $41 billion a year.

Even annual inspections don't guarantee a bridge is safe.

Last Saturday, 1,200 pounds of concrete chunks fell from a 50-year-old bridge in St. Paul over I-35E, a few miles from last summer's fatal collapse. Two cars were damaged but nobody was injured.

The bridge is safe to carry traffic, said Dan Dorgan, Minnesota's chief bridge engineer, althought he admitted "it is not acceptable for us to have concrete falling off a bridge."

Take a look here at how South Dakota bridges rank.