Endurance racing (motorsport) these classes continued to embrace the endurance format. Multiple drivers per car was an early adaptation as the rigors of endurance racing quickly overcome the abilities of most racing drivers to compete solo, although solo attempts on 24 hour races like Le Mans would continue into the 1950s. The various endurance formats were appealing to manufacturers, not only as alternatives to the expense of Grand Prix racing, but also because of its increased relevance to road going models. In automobile endurance racing, three events have come to form a Triple Crown. They are considered three of the most challenging endurance
Hallett Motor Racing Circuit Hallett Motor Racing Circuit Hallett Motor Racing Circuit is a road course about west of Tulsa in the Green Country of Oklahoma. The track has 10 turns in , and over of elevation change. The track can also be configured to run both clockwise and counter-clockwise, yielding two distinct race courses. Hallett Motor Racing Circuit hosts their own Competition Motor Sports Association (COMMA) events, as well as SCCA events. Motorcycles and high-speed go-karts also run at Hallett. As well as Central Motorcycle Racing Association sanctioned races, the track also hosts COMMA High Speed Touring dates where regular cars and sports