Autonomous vehicles interact regularly with pedestrians in urban environments, providing an interest for the research community in reducing the risks and collisions involved. The predominant cause of pedestrian collisions is represented by human error. The collision avoidance system, as part of the autonomous driver assistance systems (ADAS) has been used in this study to simulate and investigate pedestrian detection when the pedestrian is approaching from a hidden space. There may be a severe consequence in an urban environment where pedestrians represent an important traffic participant. A simulation was established to enhance the collision avoidance outcome. Simcenter Prescan and MATLAB Simulink were adopted as a simulation environment. The study aims to investigate the collision avoidance system in a scenario where the pedestrian is walking from an occluded space and is changing its trajectory. The presented work established that the collision avoidance system is effective for detecting an unexpected pedestrian and the actuation system can stop the vehicle in safe conditions to avoid a collision with the detected pedestrian.