Snaefell Mountain Course is a road-racing street circuit used for the Isle of Man TT and Manx Grand Prix Races held in the Isle of Man from 1911 and 1923 respectively. The racing is held on public roads. It is the oldest motor-cycle racing circuit still in use.
Cars have never raced on the mountain course. In fact, they've only run on the closed course a handful of times, one of which occurred last year when Subaru persuaded the organizers to let World Rally Championship driver Mark Higgins flog a mostly stock Impreza WRX STI at full tilt. He set a lap-time record for production cars at 19 minutes 37 seconds and averaged 115.4 mph.