Today’s conventionally manufactured vehicles have a range of driving aids that help keep the vehicle safe. The operation of these features depends primarily on the proper functioning of sensors, which continuously monitor surroundings to detect obstacles. However, these sensors are not always reliable. The aim of this article is to investigate the actual limits of automatic emergency braking (AEB) when a pedestrian enters the roadway, which in many cases is unpredictable, sudden, and not automatically controlled. The expected high efficiency of AEB is significantly affected by both the speed of the vehicle and weather conditions. The conclusion of this study, therefore, is used to develop a discussion on urban speed limits and their impacts on vulnerable road users.