The law firm Gray Plant Mooty conducted the five month investigation, sifting through 24 thousand records and interviewing dozens of current and former MnDOT employees.
Robert Stein, who led the investigation, told a legislative committee Wednesday that he found MnDOT didn't follow its own policies, that it had unclear decision-making procedures, and that a lack of funding may have influenced decisions.
MnDOT was closely examining the I-35 bridge before it collapsed because it was considered fracture critical - meaning the bridge would collapse if one portion failed. Stein said MnDOT officials may have decided to take the least expensive alternatives on the bridge.
"We believe that, yes, funding did influence decisions along the way," he said. "Not an ultimate decision that may have caused the bridge to collapse but decisions on how to deal with a bridge that was rated in a poor condition for 17 consecutive years without being approved."
Federal investigators still have not determined what caused the bridge to collapse on August 1. The disaster killed 13 people and injured 145.
Stein and the other investigators were careful to mention that their report was not meant to determine why the bridge collapsed. Instead, they said it was designed to offer suggestions on preventing future problems.
The report's major recommendations are to improve the bridge inspection process, to improve communication within MnDOT and to ensure that there is appropriate follow up on inspections.
Gray Plant Mooty's Kathryn Bergstrom said MnDOT's metro district office and the central bridge office didn't communicate effectively about what to do about the bridge's poor condition.
"One of the questions we asked is 'Who was the advocate for this bridge?' And I think the answer is 'They both are' and that is part of the problem because that responsibility or that advocacy has been diffused," she said.
Bergstrom and others also said bridge inspectors didn't document that the I-35W bridge had a bowed gusset plate, even though one engineer recalls observing that during an inspection.
The National Transportation Safety Board, which is conducting the investigation into the bridge collapse, announced in January that the plates that connected the steel girders of the bridge were too thin.
Several legislators suggested the federal government didn't do its job to inform other states that an Ohio bridge had gusset plate problems in 1996.
But Rep. Neil Peterson, R-Bloomington, said he was troubled that MnDOT officials didn't learn of the problems on their own. He complained that management within MnDOT was lacking.
"Lack of management and lack of identifying of red flags has darn near brought this department down," he said. "And somehow somebody better pull this up short and get their act together with this department because these are all linked."
Lt. Gov. Carol Molnau was commissioner of MnDot from 2003 until the state Senate removed her last February. Several former governors and former transportation commissioners told investigators that an elected official should not run the transportation department.
Gov. Tim Pawlenty named Tom Sorel last month to replace Molnau. Sorel sat and listened during the three hour hearing in the back of the committee room.
He later told the committee and reporters that he needed time before he can respond to the report. But he said the agency never compromised safety.
"Addressing the condition and safety needs of our bridge system has never been and never will be subject to question due to budgetary concerns," he said. "We rely on and invest in the expert opinions of our bridge engineering professionals."
Gov. Pawlenty's spokesman also issued a statement saying the governor will work with Sorel on the report's recommendations, but that until the cause of the collapse is determined, it is not possible to know whether anything in the report is relevant to the bridge collapse.