A great deal of effort has been concentrated on the longitudinal control fo
r the collision avoidance of moving vehicles. In an emergency as well as in
a normal situation, however, the steering control can be a very effective
alternative as observed in the practice of manual evasive driving. In the r
eported methods of steering control, it is found that the dynamic motions o
f the neighboring vehicles are often ignored, which may result in some dang
er of 2nd collision. Therefore, it is necessary to assess the surrounding t
raffic situation to prevent 2nd collision that can occur just after escapin
g from the Ist collision situation. In this paper, we tackle the collision
avoidance problem when steering actuation control is allowed in considerati
on of the dynamic motion of the neighboring vehicles. Specifically, a hiera
rchical control scheme is suggested as a feasible solution, and the propose
d system is verified via simulation using a software simulator called DevAC
AS (DEVeolper of Active Collision Avoidance System), which we have develope
d.