SPEED MODELS AT ENTRIES TO SIGNALISED RURAL INTERSECTIONS

Intersection design takes into account various groups of criteria that are common for intersections regardless of their location. However, road intersections located in urban areas are designed somewhat differently from those in rural areas, with greater emphasis at rural intersections placed on the issue of traffic dynamics, while service efficiency for various road users features high in the design of urban intersections. A particular problem in rural areas characterized by high vehicle speeds and a different traffic structure is posed by traffic control at the intersection by means of signals which would ensure consistency of geometric features, traffic organization and control at the intersection. In the absence of specific regulations, stakeholders increasingly ask whether the principles of control typically used in cities [5] can be applied at rural intersections. The answer to the above question required pre-tests to determine what specific features of geometry, traffic organization and traffic flows determine the quality of signalised intersection operation on high speed roads in rural areas [3]. Detailed empirical research at 38 intersections focused on vehicular traffic by group of light and heavy vehicles at individual entry lanes of rural intersections [1]. As a result, the authors were able to determine specification of the functioning of rural intersections and the impact of selected entry and intersection geometrical features, traffic features and road surroundings on the speed of vehicles approaching signalised rural intersections. The variability of the analysed factors allowed to examine the significance of the impact of individual quantitative and qualitative variables on vehicle speed and the creation of speed regression models. Proper speed modelling at intersection entries enables proper shaping of entry's geometry and configuration of detector systems and related control parameters (e.g. jednostkowe extension of the green signal). The main objective of the study work and empirical research was to create the basis for rationalization of the design of signalised intersections from the point of view of traffic performance and safety.