Secret Service arrangements for Presidential trips, which were followed in the Dallas motorcade, are designed to provide protection while permitting large numbers of people to see the President.[C2-92] Every effort is made to prevent unscheduled stops, although the President may, and in Dallas did, order stops in order to greet the public.[C2-93] When the motorcade slows or stops, agents take positions between the President and the crowd.[C2-94] The order of vehicles in the Dallas motorcade was as follows: _Motorcycles._--Dallas police motorcycles preceded the pilot car.[C2-95] _The pilot car._--Manned by officers of the Dallas Police Department, this automobile preceded the main party by approximately a quarter of a mile. Its function was to alert police along the route that the motorcade was approaching and to check for signs of trouble.[C2-96] _Motorcycles._--Next came four to six motorcycle policemen whose main purpose was to keep the crowd back.[C2-97] _The lead car._--Described as a “rolling command car,” this was an unmarked Dallas police car, driven by Chief of Police Curry and occupied by Secret Service Agents Sorrels and Lawson and by Dallas County Sheriff J. E. Decker. The occupants scanned the crowd and the buildings along the route. Their main function was to spot trouble in advance and to direct any necessary steps to meet the trouble. Following normal practice, the lead automobile stayed approximately four to five car lengths ahead of the President’s limousine.[C2-98] _The Presidential limousine._--The President’s automobile was a specially designed 1961 Lincoln convertible with two collapsible jump seats between the front and rear seats.[C2-99] (See Commission Exhibit No. 346, p. 44.) It was outfitted with a clear plastic bubble-top which was neither bulletproof nor bullet resistant.[C2-100] Because the skies had cleared in Dallas, Lawson directed that the top not be used for the day’s activities. He acted on instructions he had received earlier from Assistant Special Agent in Charge Roy H. Kellerman, who was in Fort Worth with the President.[C2-101] Kellerman had discussed the matter with O’Donnell, whose instructions were, “If the weather is clear and it is not raining, have that bubbletop off.”[C2-102] Elevated approximately 15 inches above the back of the front seat was a metallic frame with four handholds that riders in the car could grip while standing in the rear seat during parades.[C2-103] At the rear on each side of the automobile were small running boards, each designed to hold a Secret Service agent, with a metallic handle for the rider to grasp.[C2-104] The President had frequently stated that he did not want agents to ride on these steps during a motorcade except when necessary. He had repeated this wish only a few days before, during his visit to Tampa, Fla.[C2-105] [Illustration: COMMISSION EXHIBIT NO. 346 Interior of Presidential limousine used on November 22, 1963.]