This paper presents the different influence factors to vehicle's path planning, including the guide-potential shape and its parameters, the guild-potential influence scale factor, the stiffness of the elastic bands and the speed of the host vehicle. The assessment of emergency path is based on the dynamic performance of the host vehicle, the lateral acceleration and yaw rate, and its mean-square values accesses the stability of the host vehicle when following the path. In order to take evasion maneuvers more steadily, a guide-potential affecting the moving vehicles behind the obstacle is built, which encourages the host vehicle to change lane appropriately. Three different shape guide-potential models, namely half-circle-like, half-ellipse-like and parabola-like, are proposed and compared in this paper. Meanwhile, hazard map of the road environment which includes the lanes, borders and obstacles is generated. Trajectory of low hazard level is generated based on virtual elastic bands which are composed with a number of nodes. Thus, the forces acting on the corresponding nodes of an elastic band are calculated by the directional derivate of those potentials. The sum of the forces acting on each node of the elastic bands should be zero due to equilibrium condition. The simulation results show that the stiffness of the elastic bands and the speed of the host vehicle have the most significance influence to the emergency path generating, the guide-potential influence scale factor and the parameters of the guide-potential follow the second, while the shape of the guide-potential has the least influence.