“…In general traction control systems that need the vehicle longitudinal speed, the nondriven wheels, which are not connected to the drive machine, serve as an approximation of the speed, but it is not applicable when the vehicle is accelerated by four wheel driving system or decelerated by brakes equipped in these wheels (Hori et al, 1998;Yin et al, 2009). Other dedicated sensors, e.g., acoustic sensors (Cevher et al, 2009), optical sensors (Turner and Austin, 2000), sensors of magnetic markers (Hyeongcheol and Tomizuka, 2003;Suryanarayanan and Tomizuka, 2007), etc., which can obtain the chassis velocity, are too sensitive and reliant on the driving environment or too expensive to be applied in actual vehicles. The vehicle velocity can also be estimated in commercial products, like Electronic Stability Program (ESP) system (Zanten, 2000), in a much more complicated way inferred from other measurements, such as wheel speed, yaw rate and acceleration measurements.…”