This year some 25 of the teams — which consist of a driver and co-driver, from Mexico and Chile, Holland and the U.K., among other home countries — drive the route in what the organizers call Icon cars: modern, if still rare, Maseratis, Lamborghinis, Ferraris and, to mark its 110th anniversary, plenty of Aston Martins. They benefit from power steering, ABS brakes and, most welcome of all, reliable heating.