Five years after the assassination of President John F Kennedy , the American secret service have emerged with a presidential car which is they think assassin-proof . Two of these Lincoln covertibles have been ordered from Ford of America , at a cost of between 瞿15,000 and 瞿20,000 each . The cars have roofs of tranparent vinyl and 11 in wide running boards plus retractable platforms provided for agents travelling alongside men at the rear . In addition to all this there are a battery of sirens, public address speakers and red emergency flashing lights , with an electronic communications system . The secret service hint there are numerous other built-in devices to ensure the President's safety . 8 march 1968 *** Local Caption *** 577112