Where to ambush? High-ground pressure wheeled vehicles (limousines) are restricted to roads
Wheeled Vehicles that try to go off road can get stuck
While a wheeled vehicle can “Y” turn to go back the same way it came, its impossible with a convoy of cars following directly behind in the same survival predicament
Smart militaries use TRACKED vehicles that can pivot turn and go x-country at will to evade ambushes: not an option for JFK on November 22, 1963, civilian non-chalance in effect