WindShear
The Windshear Full Scale Rolling Road Wind Tunnel is an automotive wind tunnel in Concord, North Carolina. In January 2008 Wind Shear, a division of US machine tool builder Haas Automation, completed construction on one of the most advanced automotive wind tunnels in the world. The full-scale tunnel is located adjacent to Concord Regional Airport in Concord, North Carolina. The commercial operation was designed for vehicles from race industries: stock car, Formula One, Indy car, drag racing, as well as production car industries. Wind Shear's tunnel is a closed air circuit, temperature-controlled system built around a  rolling road. The rolling road, akin to a giant treadmill, is 10 ft wide by 29.5 ft long (3 m x 9 m) and accommodates full-size cars. Air and rolling road speeds are coordinated up to . Air temperature, critical to repeatable data collection, is maintained at a constant , plus or minus one degree. Air is moved through the massive air circuit at the maximum rate of per second by a motor and 29 carbon fiber blades in diameter. In wind tunnel testing, the size of the test chamber can greatly affect the quality of the test. An example of  this, the blockage effect, is the condition where air flow in the wind tunnel is partially blocked by the vehicle. The blockage becomes more critical as the cross section of the test vehicle increases relative to the size of nozzle and airstream. As the vehicle increases in size relative to the nozzle, test data become less reliable as increased blockage effects the quality of the actual windstream. Windshear's solution was to build a sufficiently large air circuit. Nozzle size is a relatively large 180 square feet (16.7 square meters).