From Wikipedia:
The Nardò Ring, is a high speed test track located near the town of Nardò, in the southern Italian region of Apulia, in the province of Lecce.
The track is 12.5 km long (just under 7.8 miles) and is perfectly round, has four lanes for cars and motorcycles totaling 16 meters in width and has a separate inner ring for trucks at a width of 9 meters. In the cars/motorcycle ring the lanes are banked at such a degree that a driver in the outer most lane need not turn the wheel while driving at speeds of up to 240 km/h. In essence, at the so called neutral speed which is different for the four lanes, one can drive as if in a straight lane. However extremely fast cars still require the steering wheel to be turned when going faster than the maximum neutral speed. For example the Koenigsegg CCR which set a speed record for a production car at the Nardò Ring did so with the steering wheel at a 30° angle. This speed record has since been beaten by the Bugatti Veyron at a private Volkswagen long straight line test track in Germany, and hence the CCR only holds the speed record for the Nardò Ring. In the process of fighting a turn as needed when going faster than the neutral speed quite a bit of potential top speed is lost and hence a fast car will go faster in a straight line than what is possible on the Nardó Ring. Even at the neutral speed in a banked turn a car runs a bit heavier than it would in a straight line, since the downforce created by the banking increaces the rolling resistance on the tires. There has only been one fatality at the ring.
The neutral speed for the four car/motorcycle lanes are respectivly:
Lane 1 - 100 km/h (~62 mph)
Lane 2 - 140 km/h (~87 mph)
Lane 3 - 190 km/h (~118 mph)
Lane 4 - 240 km/h (~149 mph)
During regular weekly working activity the maximum speed allowed on the circular track is 240 km/h. Higher speeds are only allowed at times when a client gets the track for its exclusive use.
