The "Dealey Annex" in 1964. This is the area west of the Triple Underpass, built on the land donated by G. B. Dealey. The divider with the sign on it, ran between Elm St. (top) and Main St. It ran from the underpass at a width of about 4 feet, down to 1 foot where the sign was. In addition to signs, it also held a lamp post, and would be difficult for a motorcade to cross.

The other question about the selection of the motorcade route has logically been: Why Main Street? If the Secret Service were seriously concerned about the 120-degree turn, why didn’t they simply take the motorcade down Elm St., and eliminate the turn. Elm St. was as wide as Main St., and they could certainly get the same number of spectators along it. (I don’t know if there was some form of construction on Elm that prevented this consideration, nor have I known of any Researchers investigating this.) But Main St. had always been Dallas’ traditional parade route. All major parades had occurred down Main St., which centers the heart of downtown Dallas. Additionally, the name of “Main St.” itself suggests the route a Presidential motorcade should use. If you are President of the United States, running for re-election, you don’t want to be “slinking” down side streets, but want to be parading prominently down the Main street of any American city.