San Diego’s iconic Coronado Bay Bridge may be a popular overpass for locals – but a transportation organization claims the bridge has been designated "structurally deficient" by Federal Highway Administration standards.



According to an analysis of the 2012 National Bridge Inventory by the non-profit advocacy group Transportation for America, the Coronado Bridge is not entirely up to par when it comes to key structural components.



The organization, which aims to reform how transportation dollars are spent at federal, state and local levels, says the bridge above San Diego Bay gets an average of 78,000 cars crossing through each day.



But, like thousands of bridges across the nation, Transportation for America says the local bridge is "structurally deficient," meaning it requires significant maintenance, rehabilitation or replacement.



According to this report, highway bridges consist of three components: the superstructure, which supports the deck of the bridge; the substructure, which uses the ground to support the superstructure; and the deck, the top surface of the bridge that vehicles and people cross.



During federal inspection, each feature is given a rating between zero and nine, with nine representing the best condition. Federal guidelines classify bridges as “structurally deficient” if one of the three aforementioned components is rated at four or less, which means engineers have identified a major defect in the bridge’s support structure or deck.



As it stands, the Coronado Bridge is rated a four for its deck, and seven in both its superstructure and substructure, according to the Transportation for America website. Those combined figures make it structurally deficient by federal standards, like many other popular bridges across the U.S.



The organization says a total of 69,223 bridges – or 11.5 percent of all highway bridges across the United States – are classified "structurally deficient" according to the Federal Highway Administration.



Additionally, many bridges exceed their expected lifespan of 50 years. Transportation for America says the average age of an American bridge is 42 years.



The 2.12-mile Coronado Bridge officially opened on August 3, 1969, making it nearly 44 years old, according to the City of Coronado.



As far as statewide statistics are concerned, this national bridge report says 12.8 percent -- or 3,135 -- of California’s 24,542 bridges are structurally deficient, so the Coronado Bay Bridge is far from alone in its classification.

A look at Transportation for America’s website reveals numerous ailing bridges within a 10-mile radius from the Coronado Bridge, including the Clairemont Drive bridge, which received a deck rating of two.



Transportation for America says other iconic bridges deemed "structurally deficient" include New York’s Brooklyn Bridge, Chicago’s North LaSalle Street Bridge, Steel Bridge in Portland, Ore., and Longfellow Bridge in Boston.



Transportation for America says most bridges in the U.S. are inspected every two years, but bridges that have been declared “structurally deficient” must be inspected every year.

Meanwhile, local civil engineers say it’s still safe to drive across the Coronado Bridge.

But, it could be showing signs that work needs to be done to prevent bigger problems.



“If the bridge was unsafe, it would be posted with a lower load rating or it would be closed completely,” Jim Frost of the American Society of Civil Engineers told NBC 7.



Frost says the “structurally deficient” designation for the Coronado Bridge could be attributed to smaller issues with the road or deck.



"As you drive across the bridge you might notice that there are little potholes or openings in the deck. That ultimately will lead to a worse and worse problem," he explained.

Civil Engineers say this news points to the looming problem facing San Diego and the rest of the country of neglecting our infrastructure.

"The rest of the infrastructure in the country has just been underfunded. It's continuing to be underfunded, and unless we put a plan together to fix that, we're just passing that problem to the next generation at a higher cost in the end," added Frost.

Caltrans maintains the Coronado Bridge, but NBC 7 was unable to reach them for immediate comment.