NEW YORK (MainStreet) — More than 63,000 bridges in the U.S. are in need of repair, many of them more than 40 years old and deemed "structurally deficient." The U.S. Department of Transportation (USDOT) estimates Americans cross these compromised bridges 250 million times every day, and the only solution to the problem is something few drivers are willing to face: a higher price for gasoline.

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The Highway Trust Fund (HTF), accounting for nearly half of the funding for state highway and bridge improvements, is rapidly approaching insolvency. The gas tax that feeds the fund now accounts for 18.4 cents of the cost for every gallon we buy, but hasn't been raised since 1993.

"The gas tax has not been raised in over twenty years. Many items have doubled or tripled their cost since 1993," writes Clark Barrineau in a blog for the American Society of Civil Engineers. "For example, a new car cost $12,750 in 1993, yet in 2013 a new car cost $31,252. The easiest explanation is that we are trying to build a 2014 infrastructure system with 1993 dollars. This is obviously an untenable formula."

Dr. Alison Premo Black, chief economist for the American Road & Transportation Builders Association (ARTBA), says without congressional action there soon won't be funding for any transportation project in any state.

"Letting the Highway Trust Fund investment dry up would have a devastating impact on bridge repairs," Black says. "The bridge problem sits squarely on the backs of our elected officials. The state transportation departments can't just wave a magic wand and make the problem go away. It takes committed investment by our legislators. Members of Congress need to come to grips with that. Some of our most heavily travelled bridges were built in the 1930s. Most are more than 40 years old."

While not "imminently unsafe," ARTBA says 250 of the most heavily crossed "structurally deficient" bridges are on urban interstate highways, particularly in California. With one exception, all are at least 39 years old.

The states with the highest number of structurally deficient bridges are Pennsylvania (5,218), Iowa (5,043), Oklahoma (4,227), Missouri (3,357) and California (2,769).

--Written by Hal M. Bundrick for MainStreet