The effect of four-wheel steering on vehicle handling and stability was investigated. It was found that vehicle stability is improved by steering the rear wheels in the same direction as the front wheels. The steer angle of the rear wheels should increase with increasing vehicle velocity. Transient characteristics of the rear wheel steer angle are important in achieving both good stability and steering response. One way of achieving this is to introduce a suitable time delay in the rear wheel steer angle. These results have been incorporated into the High Capacity Actively Controlled Suspension (HICAS) system. It was also confirmed by analysis and experiments that handling and stability are significantly improved by actively controling the front wheel steer angle to achieve an optimum match with the rear wheels.