The Washington, D.C.-based nonprofit Transportation for America found the region had more "structurally deficient" bridges than the national average, the report said.
"San Francisco happens to be at the top of the list," Stuart Cohen from Transportation for America said.
The Washington DC-based group reviewed federal highway data and released today's report. Any elevated roadway is considered a bridge and more than 24,000 in California were examined. San Francisco and Alameda counties are in the top five in terms of the worst with wear and tear.
"We don't want people to be scared, walking or hiking or driving across a bridge. If it's extremely unsafe, Caltrans will close it off like they did the Bay Bridge in 2009," Cohen said.
That's when Caltrans discovered a crack in an eyebar during a routine inspection. In a statement read by a spokesman, the transportation agency calls its bridge management program "robust" and in response to Tuesday's report, says more federal resources are needed.
"California needs a continued stable and reliable long-term investment strategy from the federal government that can support the state's highways and bridges," Bob Haus from Caltrans said.
The experts say bridges are designed to last 50 years. The average age of those in California is 44.4. Transportation for America believes federal funding should shift from a focus on new projects and concentrate on shoring up bridges that are showing their age.
"We've got to put more money into maintenance now or in the future it's really going to bite us," Cohen said.
Sen. Barbara Boxer, D-Calif., is chair of the Senate committee on the environment and public works. ABC7 asked her what her thoughts were about this report and she said she is working with colleagues in the Senate and the House trying to move forward a long-term transportation bill.