Jump to main content.
Minnesota Department of Transportation Go to 511
MnDOT A to Z | General Contacts | Simple Search | Advanced Search
Workzone at night

News Release

Nov. 14, 2008



Minnesota Department of Transportation
Office of Communications
395 John Ireland Blvd.
Mail Stop 150
St. Paul, MN 55155-1899

Additional Information


Search Statewide News



National Transportation Safety Board concludes investigation into I-35W bridge collapse

Cites design error in original plans as probable cause


ST. PAUL, Minn. – The National Transportation Safety Board today released the results of its investigation into the cause of the Interstate 35W Bridge collapse on Aug. 1, 2007 and made recommendations for changes in industry practice to prevent a similar tragedy from occurring on the nation’s other bridges.


During a two-day public hearing that began Thursday, Nov. 13, the NTSB cited an error in the original design of the gusset plates as the probable cause of the collapse. Construction on the bridge began in 1965 and it opened to traffic in 1967.


“The Minnesota Department of Transportation appreciates the thorough investigation that the NTSB undertook during the past 16 months, and we respect the professional manner in which the NTSB investigative staff performed this very difficult assignment,” said Tom Sorel, Mn/DOT commissioner.


“It was critical to have a definitive and complete review of the accident and history of the bridge. Only through such a process can we learn and make improvements,” he said.


As the NTSB released information during the last year, Mn/DOT took actions in response to their findings, including: