The facility features 96 km (60 miles) of private tarmac, which includes a large variety of road surfaces and curves, used as test tracks to evaluate new and prototype vehicles. More significantly, there is a high speed circuit with a straight approximately 8.7 km (5.4 mi) long. Although this portion of the track is flat and level, when standing at one end of the straight, the other end cannot be seen due to the curvature of the Earth. [2] Including banked corners at both ends of the circuit, allowing for a high entry and exit speed to and from the straight, and to increase average speed during the 20 km (12 mi) lap, the straight is especially useful for determining vehicle top speed.