In Appendix XII of the Report of the President's Commission On The Assassination of President John F. Kennedy, entitled "Speculations And Rumors", the Warren Commission asserted that "The motorcade route was decided upon November 18  and published in the Dallas newspapers on November 19 . It was not changed in any way thereafter. The route called for the motorcade to turn off Main Street at Houston, go up to elm, and then turn left on Elm Street."
Yet according to Warren Commission Exhibit No. 2709, "On March 21, 1964, a confidential source advised" the FBI "that Joachim Joesten had been interviewed on that date at the American Consulate General in Hamburg, Germany" and stated the following:
"He arrived in Dallas, TX, on December 6, or 7, 1963, and stayed for four days. He concluded that Lee Harvey Oswald is innocent of the murder of President Kennedy which can be readily seen by a review of published information...
"The most important factor is that the actual route which the president took differed from the published sketch. The sketch in The Dallas Morning News showed that the president would travel straight down Main Street in Dallas to proceed under the `triple underpass.' However, the president's car turned to the right on Houston from Main and then turned left on Elm Street which took the car past the book depository..."
Coincidentally, in her book JFK: The Last Dissenting Witness, Jean Hill recalled that the following conversation took place between her and J.B. Marshall--one of the Dallas motorcycle cops who had been assigned on November 22, 1963 to escort JFK's car down the motorcade route:
"DALLAS MOTORCYCLE COP MARSHALL: "Well, while Kennedy was busy shaking hands with all the wellwishers at the airport, Johnson's Secret Service people came over to the motorcycle cops and gave us a bunch of instructions. The damnedest thing was, they told us the parade route through Dealey Plaza was being changed."
JEAN HILL: "Changed? How?"
MARSHALL: "It was originally supposed to go straight down Main Street, but they said for us to disregard that. Instead, we were told to make the little jog on Houston and cut over to Elm.
"They also ordered us into the damnedest escort formation I've ever seen. Ordinarily, you bracket the car with four motorcycles, one on each fender. But this time, they told the four of us assigned to the president's car there'd be no forward escorts. We were to stay well to the back and not let ourselves get ahead of the car's rear wheels under any circumstances. I'd never heard of a formation like that, much less ridden in one, but they said they wanted to let the crowds have an unrestricted view of the president. Well, I guess somebody got an `unrestricted view' of him, all right."