What do we know about Baltimore’s Francis Scott Key Bridge?

A cargo ship is shown after running into and collapsing the Francis Scott Key Bridge on March 26, 2024 in Baltimore, Maryland. Picture: Rob Carr/Getty Images

Baltimore's Francis Scott Key bridge collapsed Tuesday morning, after a container ship smashed into the structure, plunging cars into the water. It is a major traffic and transportation hub for the United States East Coast and the entry point to the Port of Baltimore.

Here's what we know about the Key Bridge:

Picture: Yasin Demirci/Anadolu via Getty Images

BRIDGE HISTORY: The four-lane steel bridge opened in 1977 after five years of construction and spans 2.6km. 

It crosses over the Patapsco River, where U.S. national anthem author Francis Scott Key wrote the "Star Spangled Banner" in 1814 after witnessing the British defeat at the Battle of Baltimore and the British bombing of Fort McHenry. 

It has 56 metres of vertical clearance.

Built at an estimated cost of $110 million, it allowed for more traffic lanes and carried lower operating and maintenance costs than a tunnel.

TRAFFIC AND TRANSPORT INFO: The bridge carries 11.3 million vehicles a year, the Maryland Transportation Authority says, on the I-695 highway that circles Baltimore, also known as the Baltimore Beltway.

OTHER BRIDGES IMPACTED 

Other structures along the route include a 1km dual-span drawbridge over Curtis Creek and two 1.2km parallel bridge structures that carry traffic over Bear Creek, near Bethlehem Steel's Sparrows Point plant.

COMMUTE DISRUPTIONS: Maryland's Transportation Authority called the incident a "major traffic alert" and redirected cars to the I-95 or I-895 highways. 

Large trucks are prohibited from using the 1-95 tunnel route that goes under the Baltimore harbour.

BALTIMORE PORT TRAFFIC: Because of the bridge's collapse, ships are not leaving the Port of Baltimore, shipping and insurance sources say.

Over 40 ships remained inside Baltimore port including small cargo ships, tugboats and pleasure craft, data from ship tracking and maritime analytics provider MarineTraffic showed on Tuesday. 

At least 30 other ships had signalled their destination was Baltimore port, the data showed.