The eight-mile Bay Bridge, which links San Francisco and Oakland, Calif., and received a 32.1 percent rating, is scheduled to be replaced in 2013 by a new one that will feature the world's largest self-anchored suspension bridge -- a $13 billion job that is billed as the largest public works effort in California history.
New York's Joramelon Bridge received a 34 percent rating, but "there are no open flags" for serious problems such as corroded steel or loose concrete, according to Ted Timbers, deputy press secretary of the New York City Department of Transportation.
"Nothing needs to be repaired on this bridge at this time," he said.
Virginia's Boundary Channel Bridge over the Shirley Memorial Highway, which is rated a 42.5 percent, is due for an "investigative study" this fall that will involve testing the internal condition of the concrete to determine if it needs any rehabilitation, according to Joan Morris, spokeswoman for the state's department of transportation.
"It's not a dangerous bridge -- it's just old," says Morris, stressing that the bridge received a low rating because some of its design features are dated.
Similarly, the Bourne Bridge in Massachusetts, which was built in 1935, received the low rating largely due to its age, having undergone major rehabilitation in 2001, according to Cape Cod Canal manager Frank Fedele.
"We have started doing interim 12-month inspections," he said. "We would like to do something bigger and better, but we've got what we've got. But when you take the time and effort we put into inspections, I'm very satisfied that our bridge is safe."
In California's Caltrans district 7, which covers Los Angeles and Ventura counties and where two bridges -- Metrolink over I-710 and Noakes Street Bridge over I-710 -- made the list, all state bridges have been retrofitted except one, which is scheduled for replacement, said Dave White from the state's DOT.
Across the country, two-thirds of the most heavily-trafficked problem bridges in each state have not received any work beyond regular maintenance since last year's I-35W bridge collapse, according to an Associated Press review.
Only 12 percent of those bridges had their structural defects fixed and 24 percent had received a partial improvement such as short-term repair work.
None of the 1,020 bridges reviewed by the AP were in immediate danger of collapse, according to state engineers and officials.
Smaller counties across the country, some of which have high numbers of deteriorating small bridges, are taking steps to fix or replace them.
Of the 155 bridges in Attala County, Miss., 76 are rated for either major rehabilitation or total replacement, according to county engineer Christian Gardner.
"We did have one bridge that fell in under traffic some years ago," he said. "A tractor going across fell to the bottom of the creek, but there were only minor cuts and bruises."
The county was rated the one with the second-highest number of failed, imminent, critical and serious bridges, according to an analysis of federal statistics by geo-spatial engineer Sean Gorman.
The county with the third-highest number, Pennsylvania's Allegheny County, also has an ambitious program to inspect and maintain its 500 bridges, recently receiving an additional $1.1 million for bridge repairs.