2. Methods and materials
In order to determine the effects of speed bumps of different heights on speed decreasing, in this study we have compared vehicle speeds (before and after speed bumps installation) at three locations in Belgrade. These are the locations where the citizens filled claims to City Department of Transport for speed decrease of vehicles by installing speed bumps. The common for all three locations is that they have similar geometric characteristic (width from 6.8 m to 7.2 m, a longitudinal slope of maximum 3%) and functional characteristics (housing streets intended for two-way traffic with one lane in each direction) and that at all locations speed limit is 50 km/h (Table 1). Although the analysed locations are not near schools, an increased presence of children and pedestrians was perceived, especially on workdays in the period from 12 to 14 o’clock, that coincides with the period when the first shift of pupils come back from school and the second one go to school.