The basic assumption in car following theories is that the speed and acceleration of a car are dependent upon the vehicle immediately preceding it (in a single lane of traffic). The General Motors Corporation has done some extensive studies of car following behaviour. They have used two-vehicle platoons to estimate driver behavioral responses. The Louisiana State University (LSU) has developed a new technique; it had used GPS to record aspects of vehicle motion, independently, for vehicles under open roadway conditions. A GIS was also used as tool for the creation of mapped road networks, route analysis and linear referencing.