Lessons for Baltimore: How Minneapolis recovered from its I-35W bridge collapse 17 years ago

By Alicia Wallace, CNN

Minneapolis (CNN) — The collapse of the the Francis Scott Key Bridge in Baltimore on Tuesday is unfortunately not the first deadly collapse of a major interstate bridge in the US. But the response to a bridge failure in Minneapolis 17 years ago, one of the most catastrophic bridge failures in recent memory, could serve as a roadmap for Baltimore moving forward.

On August 1, 2007, when cars were bumper to bumper in evening rush hour traffic along Interstate 35W in Minneapolis, the heavily trafficked, eight-lane bridge that spanned the Mississippi River suddenly failed and collapsed into the river and railyard below. Thirteen people were killed, and nearly 150 more were injured.

In addition to the tragic loss of lives and the immediate damage, the collapse of the I-35W bridge cut off a major transportation artery for the Twin Cities. About 140,000 cars a day traversed the I-35W bridge that once stood more than 100 feet above the Mighty Mississippi.

The loss of the I-35W bridge was initially estimated to sap $113,000 per day (about $17 million total in 2007 and $43 million in 2008) from the state’s economic output, according to projections from the state of Minnesota. Concern swelled about how traffic would snarl elsewhere in the state.

The enormous traffic jams did not emerge as expected, and it took only 13 months for a brand new bridge to be built.

“The economic impact was orders of magnitude less than people had feared,” Christopher Phelan, an economics professor at the University of Minnesota, told CNN.

“There was a lot of almost instant adaptability.”

A city of lakes, moving swiftly

In the days and weeks that followed, the Minnesota Department of Transportation (MnDOT) restriped several of the major highways and neighboring interstates to turn the shoulders into driving lanes, he said.

The City of Lakes, by its nature also a city of bridges, and MnDOT immediately inspected the bracket plates on every truss bridge in the state and established a program to repair and replace any and all structurally deficient bridges within 10 years, MnDOT Commissioner Nancy Daubenberger told NPR 2017, on the 10th anniversary of the collapse.

The federal government moved swiftly as well: The House of Representatives and the US Senate voted unanimously for $250 million in emergency funding for Minnesota, and the bill was signed into law by President George W. Bush on August 6, just days after the collapse.

By mid-September, MnDOT had enlisted one firm to both design and build the replacement bridge, which was ultimately completed far faster and cheaper than projected.

The I-35W Saint Anthony Falls Bridge was opened in mid-September 2008, a startlingly fast turnaround by infrastructure standards.

On Tuesday night, the I-35W bridge was lit in the colors of the Maryland state flag.

US bridges can take several years to be built, with some construction projects taking much longer.

“We see things that are taking 10 years to build that would have taken a year 50 years ago,” Phelan said. “Those things that are causing it to take 10 years instead of a year are not laws of nature. Those are laws of humans that can be set aside — and they have been set aside — for emergencies.”

On Tuesday, Minnesota Gov. Tim Walz made a post on social media site X calling the news of the collapse “heart-wrenching” and added that “as we pray for the people of Maryland, we’re offering any resources they may need as they grapple with this tragedy.”

It’s not a complete apples to apples comparison between the I-35W bridge and the Key Bridge. The Key Bridge had about 22% of the daily traffic of the I-35W Mississippi River Bridge; however, the Minneapolis bridge was about 22% the length of the truss bridge in Baltimore.

Additionally, the Key Bridge’s collapse closed the nation’s ninth-busiest port.

“And that’s going to last until the salvage companies can come and clear that channel,” Ryan Petersen, chief executive officer of logistics technology firm Flexport, told CNN in an interview. “It could be weeks, it could be months before they’re able to open up the channel again and make it safe for ships to continue serving the Port of Baltimore.”

Unspooling economic impacts

Ships will be re-routed, as will the daily commutes, the commercial traffic and those who used the bridge for non-work trips, said civil engineer and author David Levinson, a former University of Minnesota professor who researched the I-35W bridge.

“One of the things that we saw with the 35W bridge is that we lost 140,000 trips per day on that bridge,” said Levinson, who is now a professor of transport engineering at the University of Sydney in Australia. “And we looked at the counts on all the other bridges, and they only increased by 90,000, which means about 50,000 trips, they vanished into the ether … they either were not made or they went to different destinations.”

Five months after the bridge collapsed, several small businesses closed up shop, citing diminished customer traffic, the Minneapolis Star-Tribune wrote at the time. The collapse was declared a federal disaster, allowing for businesses to get low-interest loans, but there were very few takers.

Some business owners at the time said they didn’t want to take on the debt for operations that were no longer economically viable.

However, the full extent of evaluating the business impact was muddled by another disaster: the broader financial crisis that would result in the Great Recession, Levinson said.

The I-35W bridge failure and collapse resulted in an estimated economic loss of $71,000 to $220,000 per day, depending on how drivers adjusted their trips, Levinson and fellow professor Feng Xie wrote in a 2011 study that was published in the Transportation Planning and Technology journal.

Levinson and Xie also found that MnDOT’s quick implementation of major traffic restoration projects had the potential to save the “road-users” $9,500 to $17,500 per day.

“This translates into a benefit-cost ratio of 2.0-9.0, suggesting these projects are highly beneficial in an economic sense,” Levinson and Xie wrote.

In the immediate aftermath of the Key Bridge collapse, Levinson told CNN that this event should hopefully bring attention to vulnerabilities of critical pieces of infrastructure.

“This kind of thing, I suspect, is not going to be the last one,” he said. “We need to be thinking about ways of defending against this, not just in terms of random events, but in terms of intentional events.”

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CNN’s Lizzie Jury contributed editorial research to this report