When a highway bridge spanning the Mississippi River collapsed last August in Minneapolis, killing 13 people, calls for action came from the highest levels. President Bush visited the scene of the disaster and assured the nation, “We in the federal government will respond,” and Congress allocated nearly $200 million for repairs.

But since then, very little has changed in how the country ensures bridges are safe. Throughout the U.S., bridges continue to be inspected only every two years, just as they were before the tragedy in Minnesota.

And although a disaster may have been averted on a Philadelphia bridge this week, it was only thanks to the careful watch of a single engineer.

Peter Kim wasn’t scheduled to inspect a certain overpass outside Philadelphia until next year, but the alert contractor, passing through the area on his way from lunch, spotted a 6-foot crack in a 40-year-old column on Interstate 95, the main highway corridor from New England to southern Florida.

“I passed by this column and saw that it had deteriorated to a point that needed immediate attention,” Kim said. A decision to close a stretch of the bridge and a portion of I-95 was made within minutes.

Around the country, 74,000 bridges are classified as structurally deficient. Just this week in Minnesota, another bridge was closed to traffic — its condition so poor that it may be beyond repair. Experts believe another collapse is all but inevitable.

“I would say that chances are we will have something occur in the future, [in] the next year or two, that will probably take lives again,” said Professor Kevin Womack, professor of civil engineering at Utah State University.

U.S. Transportation Secretary Mary Peters, reacting to the crack in Philadelphia, warned that Congress is siphoning money away from inspections, funneling it into pet projects.

“Those who say we need a more focused federal program, I agree: We should focus on national priorities, not on lighthouses [and] museums,” Secretary Peters said.

These troubled bridges are a problem with no easy solution: Engineering estimates say it will take $1.6 trillion to repair and replace them.

FOX News' Greg Kelly contributed to this report.