The internal review was conducted by a law firm hired by Christie, whose top staffers have been accused of planning the traffic tie-up at the George Washington Bridge in September 2013 as political payback after Mayor Mark Sokolich of Fort Lee, New Jersey, declined to endorse Christie's re-election.
"What we found was that Governor Christie had no involvement in the decision to close these lanes and no prior knowledge of it," said attorney Randy Mastro of the law firm Gibson, Dunn & Crutcher, which was hired to conduct the investigation.
"Not a shred of evidence of it," Mastro told a press conference in New York.
The report has no legal weight and is eyed with suspicion by many critics because it was ordered by Christie, who in January fired the staffers and denied any involvement.
The report doubted the veracity of a conversation between David Wildstein, a Christie appointee to the Port Authority of New York and New Jersey, which oversees the bridge, and Christie's press secretary after the scandal broke in December, in which Wildstein said he had informed the governor of the closings as they were occuring.
Even if Wildstein had mentioned a traffic issue in Fort Lee to the governor, Christie does not recall it, the report said.
The staffers allegedly involved were not interviewed. New Jersey lawmakers and the U.S. Attorney's office in New Jersey are undertaking parallel investigations into the traffic tie-up.
The 344-page report said the two-month internal investigation involved 250,000 documents and 70 interviews, but excluded some of the main players in the scandal, such as Bridget Anne Kelly, the governor's former deputy chief of staff, and Bill Stepien, Christie's former campaign manager.
"Witnesses lie, documents don't. We have hard evidence," Mastro said. "If we had found evidence to the contrary, we would have reported that."
Instead, blame for the traffic nightmare lies chiefly with Kelly and Wildstein, the report said.
"(Kelly and Wildstein) knowingly participated in this plan to realign toll lanes leading onto the George Washington Bridge at Fort Lee, at least in part, for some ulterior motive to target Mayor Sokolich," the report said.
Also blamed were Stepien and Bill Baroni, then deputy executive director of the Port Authority.
"(Stepien and Baroni)knew of this idea in advance, but we found no evidence that they knew of the ulterior motive here, besides the claimed purpose of conducting a traffic study," the report said.
Mastro said the investigation was a "costly" process that will be paid for by New Jersey taxpayers, but declined to confirm a New York Times report that put the bill at $1 million.
"This is a vindication in that what he (Christie) said all along proved to be true. It's a sad day in that we did find that someone in the governor's office, Bridget Kelly, and someone in the Port Authority, David Wildstein, abused the public trust," he said.
The report also recommends changes in the operation of the governor's office and other institutions to make it more transparent.
It also denounces as lies the allegations by Hoboken Mayor Dawn Zimmer, who shortly after the so-called Bridgegate scandal broke, went public with accusations that Lieutenant Governor Kim Guadagno warned her that Christie would withhold Superstorm Sandy recovery funding if Zimmer did not support a development project in her city. Guadagno has called the accusations false and illogical.
"Our investigation has concluded that Mayor Zimmer's allegations are unsubstantiated and, in material respects, demonstrably false," the report said.
"Mayor Zimmer herself has called the sequence of events that she has alleged 'unbelievable.' Based on our investigation, we would have to agree," the report said.
