Sensitivity of street network capacity under the rain impact: case study of Belgrade

It is generally know that adverse weather conditions cause changes in urban transportation system. Research of weather impact on the urban transportation system was additionally intensified by actualisation of climate changes problem. In urban area, precipitation may reduce the efficiency of transportation systems, since it often results in larger travel times and higher congestion levels in street networks. Therefore, it is important to examine the impact of precipitation on the urban street capacity. In accordance with climate characteristics of research area, the focus of this paper was on the rain impact. Impact of rain was analysed only in the context of transport supply, and not of transport demand. Sensitivity of the street network capacity was chosen to represent transportation system supply. It was analysed through the changes in saturation flow rate under the rain. Results of the research have shown significant sensitivity of street network capacity on the rain impact. Moreover, the rain impact was quantified by the capacity sensitivity coefficients, which were implemented in procedure of capacity calculation.