Giacomo Agostini 1967 he battled Hailwood in one of the most dramatic seasons in Grand Prix history. Each rider had 5 victories before the championship was decided in Agostini's favor at the last race of the season. Agostini dropped a bombshell on the Grand Prix world when he announced he would never again race at the Isle of Man TT, after the death of his close friend, Gilberto Parlotti during the 1972 TT. He considered the 37 mile circuit unsafe for world championship competition. At the time, the TT was the most prestigious race on the motorcycling calendar. Other top riders joined
Road racing Rindt won the Formula One drivers' championship posthumously, the only man to do so, underlining the continuing risks associated with road racing. When motorcycle racer Gilberto Parlotti was killed while competing in the 1972 Isle of Man TT, it sparked a rider's boycott of the event led by multi-time world champion, Giacomo Agostini, a close friend of Parlotti. Once the most prestigious race of the year, the event was increasingly boycotted by the top riders, and in 1976, the Isle of Man TT finally succumbed to pressure for increased safety in racing events and had its world championship status revoked