Study of the impact of type and condition of the road surface on parameters of signalized intersection

This paper explores the effects of the road surface type and condition on the traffic flows management mode in case of directive management. The subject matter of the study is the process of traffic flow movement at a signalized intersection. The scope of the study is the method of assessment of effect of the road surface type and condition on the capacity rate of the signalized area and therefore its effects on the traffic flow management mode. Building on the existing scientific data, the authoring team carried out studies in the area of signal control and determined a number of parameters that have an effect on traffic management modes in urban environment. The analysis of papers on the saturation flow value that is used to calculate the parameters of a signalized intersection and experimental findings showed that this value is influenced by the tyre friction coefficient which is the main parameter of the road surface type and condition. It was revealed that these parameters of the road surface have their effect on the parameters of a signalized intersection, i.e. cycle length and timing. The study showed that there is a correlation between this value (friction coefficient) and the capacity of the managed area (saturation flow) resulting in the change of the traffic lights cycle, which is also corroborated by the conducted field experiment on a signalized intersection. Saturation flow rates for the main road surface types and conditions were calculated (dry and wet asphalt, snowy and icy surface). The values of cycle length increase required in case of change of the road surface type or condition were defined.