In this study, we report on the development of a steering assistance control system that feeds back information on the outside environment collected by laser sensors to the vehicle driver. The system consists of an emergency avoidance assistance control program that performs obstacle detection and avoidance, as well as a cornering assistance control program that operates by detecting the white lines painted on roadways. Driving simulator experiments were conducted in order to confirm the effectiveness of these functions, as well as to improve understanding of the synergistic effects of the steering assistance and chassis control functions: camber angle control and derivative steering assistance (DSA) control. In our emergency avoidance experiments, which were assisted by the obstacle detection function, the automatic override function successfully intervened to prevent accidents in situations where it determined that manual steering by the driver would be too late to avoid the detected obstacle. In our experiments involving cornering assistance by white line detection, smoother steering around curves was facilitated by the system’s ability to set up an optimal approach earlier than could be expected by the curve recognition processes used by human drivers. In addition, vehicle stability at the approach and exit of a curve was enhanced by our steering system, which helps stabilize driving in critical cornering areas by effective use of camber angle control. Taken together, these steering assistance controls not only improve safety but also enhance the vehicle speed range because steering delays are minimized by the phase advances to actual steering behavior provided by the DSA control. It is expected that these systems have the potential to provide significant improvements in automotive safety.