Majority of U.S. bridges lack impact protection. After the Key Bridge collapse, will anything change?

In the wake of the collapse of the Francis Scott Key Bridge, which plunged into the Patapsco River in Maryland after the cargo ship Dali slammed into one of its support columns, CBS News has learned a majority of bridges in the U.S. lack any form of impact protection.

Accidents like the one that destroyed the 47-year-old Baltimore bridge aren't new. A similar collision in 1980 at the Sunshine Skyway Bridge over Tampa Bay killed 35 people. After that incident, codes changed and all bridges built after 1991 were required to have increased protection. 

Structures called fenders and dolphins — which absorb impact, similar to the bumper on a car — are some of the methods used to keep bridges safe.