Pedestrian collision avoidance in urban environments is an important active safety technology to protect vulnerable road users and realize zero-traffic-accident society. Especially, reduction of vehicle-pedestrian collision accidents by using active vehicle control technology is a promising approach. This paper focuses on the driving situation which drivers need to negotiate pedestrians. This paper describes an autonomous pedestrian collision avoidance system by automatic braking. The intensity of braking maneuver is determined by the application of Potential Fields theory with considering occlusions. Finally, the effectiveness of the autonomous collision avoidance system is verified by computer simulation which employs driving scenario from a near-miss incident database.