In this paper, we suggest a new control algorithm for driver's intention judgment for collision avoidance using a steering system to improve the emergency steering system performance. Most of the collision avoidance systems proposed by previous works relied only on the braking systems.Recently the automotive industry began to consider ways to avoid collisions using the steering system. It is not hard to imagine that any steering-assisted collision avoidance algorithm must judge a driver's intention for lane change before any attempt at longitudinal avoidance is made.To improve the accuracy of driver's intention judgment and thus the performance of the emergency steering system, we developed a new algorithm based on on-center handling characteristics generated by the steering system. The performance of the proposed driver's intention algorithm was validated in the test of real vehicles as well as in the SILS environment. It was shown that the driver's intention index developed in this study accurately represented the actual level of driver's intention involved in the lane change.