The above is a clue as to what separates the Panamericana from other modern, re-creations of road races. It remains a true, high-speed race (stage rally) mainly through the mountains, and as such, is extremely dangerous. Mechanical attrition for the more classic cars often leads to burst brake lines and overheated engines, but crashes are also common on the winding roads. In 1999, Bernardo Obregón and his co-driver Alda Arnauda were killed after their Volvo PV544 left the road during the Mil Cumbres mountain stage. In 2006, a 19-year-old co-driver survived a serious head injury that left him in a coma after his Jaguar E-Type Roadster crashed into a pine forest; Rusty Ward, another competitor, rolled a Studebaker from a bridge into a river, having finished the event in a similar fashion the previous year. In 2012 there were two more fatalities, but one was from a heart attack. It is obvious, therefore, that the race should not be classed with road-rallies in the style of the recreated Mille Miglia. However, since 2012 the race cars' top speed is limited to 144 mph on the closed-road sections, by restricting the engine's RPM (engine revolutions per minutes) by a chip in the electric ignition, and additional safety measures have been required.