Americans make an estimated 204 million trips back and forth each day over nearly 59,000 bridges that are "structurally deficient," and in need of repair, according to an analysis of U.S. Department of Transportation data.

American Road & Transportation Builders Association - artba.org

American Road and Transportation Builders Association - artba.org

The analysis, conducted by the American Road and Transportation Builders Association, found that the bridges may not pose an immediate threat to travelers, but could deteriorate to that point if not addressed soon.

"These bridges need to be fixed so they don't get to a point where they are unsafe for the traveling public," Alison Premo Black, chief economist and researcher at ARTBA, told ABC.

According to the American Road and Transportation Builders Association's analysis, bridges are labeled as "structurally deficient" if they receive "poor" ratings for key structural elements like the substructure, deck surface, and superstructure.

North Carolina Department of Transportation - ncdot.gov

The Washington Post notes that decrepit bridges pose travel restrictions for heavy tractor trailers, buses, and other large vehicles, which "can cause delays and those delays, ultimately, may cost the average consumer money."

In another article mapping the United States' deficient bridges, the Post's Christopher Ingraham notes:

Overall, about one quarter of our nation's bridges are either obsolete or deficient. This means that roughly 1 out of every 4 bridges you drive over is in need of work done.

WONKBLOG - washingtonpost.com

Numbers Don't Lie: America's Bridges Are In Trouble

It should be noted that ARTBA is a trade association that advocates for investment in roads and bridges, so they have a financial interest in highlighting the shoddy state of America's travel infrastructure. Nevertheless, Paul Jacobs, a California legislative analyst specializing in transportation, alerted ATTN: to state figures that show similarly high numbers of "distressed bridges" in need of repair. A recent Federal Highway Administration study also shows a high number of deficient bridges.

Wikimedia Commons - wikimedia.org

There are frightening examples of what structural repairs and other design flaws can lead to if they go unchecked.

In 2007, in what was described as an overlooked design flaw, the I-35W Mississippi River bridge in Minneapolis collapsed, leaving 13 dead and 145 injured.

Flickr/Tony Webster - flickr.com

The ARTBA report highlights a disturbing trend in the nation's infrastructure, which receives insufficient funding in the face of crumbling roads and bridges — an equation that poses disturbing possibilities, and, in some cases, results. In November, 2014, structurally deficient bridges were the subject of a "60 Minutes" segment that touched on the broader issue of collapsing public infrastructure.

CBS / 60 Minutes - cbsnews.com

"[O]ur infrastructure is on life support right now... there are bridges that need to be really replaced or repaired in a very dramatic way," former Secretary of Transportation Ray LaHood told "60 Minutes" reporter Steve Kroft.

In the ARTBA analysis, researchers noted that the most distressed bridges are in Pennsylvania, Oklahoma, and Iowa. A majority of the most-crossed compromised bridges are found on urban highways in California.