Underestimation tendencies of vehicle speed by pedestrians when crossing unmarked roadway.

To make safe road crossing decisions, the pedestrians need to estimate the distance and speed of oncoming vehicles, in order to make conclusions about the available time gap they need for their road crossing. Since the speed represents combination of distance and time, we focused on pedestrians' ability to estimate the speed of the oncoming vehicles accurately. The aim of this study was to find some characteristics important for the speed mis-estimation tendencies and its values. Seventy participants estimated speed 3920 times in total. Research included three experiments. One vehicle participated in the first experiment, while second and third experiments involved two vehicles, with various combinations of vehicle positions and speeds. Initially it was determined that the pedestrians had tendencies to speed underestimation rather than its overestimation and accurate estimation. When the participants estimated the speed of one vehicle, they were more inclined to underestimation of higher speeds (over 50 km/h). On the other hand, in the situations where the participants estimated the speed of two vehicles, they showed a serious tendency towards underestimation of lower speeds (under 50 km/h) which was completely opposite. The factors such as driving experience, age and gender were identified as statistically important in terms of speed underestimation value. We determined that an increase in task complexity, with introduction of a larger number of vehicles, resulted in more severe speed underestimation. Finally, we identified some of the most risky traffic situations in terms of speed underestimation tendencies showed by our participants.