Addressing what some witnesses described as a "flashing light'' right before the accident, Stevens said, "We are confident that any theories concerning flashing lights …can be discarded as a cause for that crash.''
Some had theorized that the driver, Henri Paul, was blinded by a flash of light that sent the car careening into the pillar.
Stevens also addressed the theory that Paul was part of a plot to kill the princess and Fayed. Stevens said that theory was disproven by the fact that the princess and Fayed changed their plans unexpectedly late in the evening of the crash.
"At 7 p.m. that evening, Dodi al Fayed and the Princess of Wales left the Ritz Hotel to go to Dodi al Fayed's apartment," he said. "They had no intentions of returning to the Ritz Hotel that night.''
Stevens said that the couple had planned to dine that night at a well-known Paris restaurant and were on their way there, when, "because of the attention of the paparazzi during the journey, Dodi al Fayed instructed his chauffeur to drive instead to the Ritz Hotel.''
At this point, Paul was unexpectedly called back to the hotel to drive the couple for the remainder of evening.
"Until he was telephoned at 10 p.m. by the Ritz Hotel night duty security officer, he cannot have known that he would be returning to the Ritz Hotel, nor did anyone else,'' Stevens said.
Much has also been made about the fact that the princess was embalmed soon after her death, which made a proper autopsy impossible.
Stevens said Diana was embalmed "for presentation reasons'' and that the decision was made by the embalmer at the time.
The report comes amid a minor media renaissance surrounding Princess Diana and the ever-embattled royal family.
"The Queen,'' a Hollywood movie about the royals' muted, baffled response to Princess Diana's death has generated Oscar buzz. On Tuesday, Diana's sons, Prince William and Prince Henry, announced plans to hold a massive concert this summer at Wembley Stadium to commemorate what would have been their mother's 46th birthday.
Also, a public inquest will be held in England next month to determine the cause of Diana's death.
And Burrell resurfaced this fall to resume his years-long waltz with the press with a new book about Diana's previously unreported private thoughts, feelings and letters. The former butler's 2002 revelation of a note that Diana wrote to him in 1996 sparked the latest investigation.
"My husband is planning an 'accident' in my car, brake failure and serious head injury to make clear the path for him to marry,''' the note said.
Stevens said that the note was investigated and that while there seems to have been "some premonition'' on the part of the princess, he dismissed the notion that there was any sort of plot to kill her.
"It has been part and parcel of what we've considered,'' he said, wearily.
Additional reporting by ABC News' Max Sandgrund.