INTERSTATE HIGHWAY SYSTEM
Collapse Spotlights Weaknesses in U.S. Infrastructure
Friday, August 3, 2007
The bridge that lies crumpled in the Mississippi River is the latest link to fail in a national highway system rapidly deteriorating under the strain of ever-increasing traffic volume and inadequate upkeep, transportation experts said yesterday.
Once the sturdy pride of post-war America, the federal interstate system is now a vast network of aging roads and bridges, including many -- such as the span that collapsed in Minneapolis -- that engineers consider deficient or obsolete.
Despite record spending on highways, experts and engineers said federal funds aren't enough to save the interstate system's half-century old bridges and 47,000 miles of highway from further decay, as a network designed to connect the nation teeters under a crush of commuter traffic.
"We're falling further and further behind," said Robert Poole, director of transportation studies at Reason Foundation and an adviser to the Federal Highway Administration. "We're prospering as a nation, driving more as commuters and shipping more goods, and that's pounding the highways and wearing them out."
According to a 2005 Highway Administration report, more than 75,000 of the nation's roughly 600,000 bridges -- 13.1 percent -- were rated "structurally deficient," meaning some components of the bridges' decks or support structures were rated poor or worse. While not necessarily unsafe, the structurally deficient designation often requires speed and weight restrictions to lessen the risk of collapse.
Concerns about bridge reliability pushed the state of the country's infrastructure into the political arena yesterday, as Senate Majority Leader Harry M. Reid (D-Nev.) called the Minneapolis bridge collapse a "wake-up call."
"We have all over the country crumbling infrastructure -- highways, bridges, dams -- and we really need to take a hard look at this," Reid said in a television interview.
Congress approved a six-year, $286 billion transportation funding package in 2005 that boosted highway and mass transit projects. But the government will need to spend $188 billion in the next 20 years just to fix the nation's flawed bridges, according to a 2005 study by the American Society of Civil Engineers.
Bridges in the Washington region are, on average, in better condition than elsewhere in the country, although hundreds of area spans are in substandard shape. Of the 245 bridges in the District, 9 percent were graded structurally deficient in the Highway Administration survey, along with 9 percent of Virginia bridges and 8 percent of Maryland bridges.
Engineers on the $2.4 billion Woodrow Wilson Bridge Project, one of several bridge projects underway in the region, said the new bridge is designed to avert the kind of catastrophe that occurred in Minneapolis.
"A majority of the interstate bridges in this country are [at the end of] service life," said Ronaldo T. "Nick" Nicholson, the Virginia Department of Transportation's manager for the Woodrow Wilson Bridge project. "In Minnesota, they were trying to extend the life rather than replace it."
Though engineers have not yet determined why the Minneapolis bridge failed, bridge experts said its collapse was not necessarily the result of a physical breakdown. Of the 1,502 recorded bridge failures between 1966 and 2005, almost 60 percent were caused by soil erosion around the underwater bridge supports, according to Jean-Louis Briaud, a civil engineer with the Texas Transportation Institute.