The National Transportation Safety Board recommends the state assess the Mackinac Bridge for risk of collapse if a ship hits it. That comes as part of the federal agency’s ongoing investigation into the Francis Scott Key Bridge collapse in Maryland last year.
In an interim report released Thursday, the agency named 68 bridges that needed to be assessed to modern risk standards for vessel collision. The American Association of State Highway and Transportation Officials established those standards in 1991 and revised them in 2009.
The association recommended that states evaluate older bridges against the updated standards both times, according to the NTSB.
In a press conference on Thursday, NTSB Chair Jennifer Homendy said the recommendations are meant to prevent another incident like the Maryland bridge collapse.
“What we are telling bridge owners is that they need to know the risk,” she said. “And determine what actions they need to take to ensure safety.”
To be clear, the Mackinac Bridge is not at risk of imminent collapse. The problem is that the state may not know if the Mighty Mac can withstand a hit from a large, modern cargo ship, the agency said. And the Straits of Mackinac experience enough heavy shipping traffic that the risk is there, according to the agency's findings.
The bridge was built in 1957, when cargo ships were much smaller. The Mackinac Bridge is five miles long, making it the longest suspension bridge in the western hemisphere.
The agency also evaluated other major Michigan bridges, including the Sault St. Marie Bridge in the Upper Peninsula and the Blue Water Bridge in Port Huron. The Ambassador Bridge in Detroit, built in 1929, was not included in the report.
The Michigan Department of Transportation declined to comment, and instead offered a statement from the bridge owner, the Mackinac Bridge Authority.
“We were made aware of the NTSB report and are reviewing it,” a spokesperson said. “As always, the Mackinac Bridge Authority's highest priorities are the safety of our state's most iconic bridge and the travelers who use it.”
Bridge owners should report the findings of their evaluation to the NTSB, according to the report. And if the bridge’s risk of collapse is above guidelines, bridge owners should “develop and implement a comprehensive risk reduction plan” to “reduce the probability of a potential bridge collapse from a vessel collision,” the report said.
“What we are trying to do is prevent something in the future,” Homendy said. “That is always what we’re trying to do in issuing our safety recommendations.”
