In standard 2 wheel steering system, the rear set of wheels are always directed forward and do not play an active role in controlling the steering. While in 4 wheel steering system, the rear wheels do play an active role of steering, which can be guided at high as well as low speeds. Production cars are designed to under steer and rarely do them over steer. If a car could automatically compensate for an under steer/over steer problem, the driver would enjoy nearly neutral steering under varying operation conditions. Also in situations like low speed cornering, vehicle parking and driving in city conditions with heavy traffic in tight spaces, driving would be very difficult due to a sedan's large wheelbase and track width. Hence there is a requirement of a mechanism which result in less turning radius. We have developed an innovative 4 wheel steering design to implement a mechanism that can serve the purpose of changing in-phase and counter-phase steering of rear wheels depending upon the conditions of turning and lane changing with respect to front wheels, thus enhancing the manoeuvrability of a sedan in accordance with its speed.

Our 4 wheel steering system gives 64.4% reduction in turning circle radius of a sedan which is reduced from 5.394m to 1.92m, considering Honda civic as a standard car for our calculations, and steering ratio therby obtained is 8.177:1 which gives much better manoeuvrability and control on the car even while driving at high speeds.