The three-mile oval test track at Navistar Proving Grounds consists of three lanes of asphalt road surface designed to carry all light vehicles and heavy truckloads of up to 32,000 pounds per axle. Each of the three lanes has specific uses designed to maximize track utility and safety. As a vehicle moves radially outward in the corners, it encounters a progressively steeper bank. The oval is used for a wide variety of tests as well as general pretest warm-ups and conditioning work. Its limited-access feature allows engineers and technicians to concentrate on subtle NVH and ride/handling problems as required.
The west straight, south curve and east straight are all 4,220 feet (0.8 mile) long with only the north curve measuring a shorter 3,170 feet (0.6 mile). All lanes are 12 feet wide. Because of its extremely flat profile, most brake testing is performed on the east straight.
Should a test procedure require speeds in excess of 90 mph in the straights or 80 mph in the corners, special precautions in the form of track warnings, competition seat belts, strobe lights, roll bars, helmets, etc., may be required. In special cases, the oval can be closed to other traffic to accommodate unusual events such as reverse direction or multi-lane tests.