This work proposes an automated steering control system for passenger cars. Feasibility of a control strategy based on a front sensor and a Global Positioning System (GPS) has been evaluated using computer simulations. First, the steering angles can be estimated by using the driving data provided by the front sensor and GPS. Second, the road curvature estimator for real-time situation is designed based on its relationship with the steering angle. Third, accurate and real-time estimation of the vehicle's lateral displacements with respect to the road is accomplished. Finally, a closed-loop controller is used to control the lateral dynamics of the vehicle. The proposed estimation and control algorithms are validated by computer simulation results. They show that this lateral steering control system achieves good and robust performance for vehicles to follow a reference path.