The National Transport University Bulletin

Abstract

The paper examines theoretical and methodological approaches to determining the carrying capacity of highways and bridges. The object of the study is traffic flow on highways and bridge crossings. The purpose of the work is to analyze the theoretical and methodological approaches to determining the carrying capacity of highways and bridges. The research method is analytical, numerical modeling. Conclusions. The main factor on which the maximum intensity of traffic on highways depends is the average speed of the traffic flow, which in turn depends on the average speed of free traffic and its decrease depending on the composition of the traffic flow, the radius of horizontal curves and the longitudinal slope of the road. Theoretically, the complete failure of a road can be considered as a state of its capacity when the traffic load on the road becomes saturated and the traffic load factor is close to unity. Therefore, the road failure criterion for traffic intensity must be determined based on the estimated traffic intensity according to DBN B.2.3-4 and the theoretical (full) carrying capacity. Based on the regulatory requirements for the operational condition of roads (evenness and roughness of the surface), the calculated value of the permissible speed of the car in the car-road subsystem is determined. The ratio for determining the carrying capacity of traffic lanes of highways, bridges and approaches to them is presented. An example of calculating the intensity of traffic flow through a bridge crossing and on the approaches to it is considered, depending on the dimensions of the bridge, the longitudinal slope of the roadway, the radius of the curves in the plan, the share of passenger cars in the traffic flow. Graphical dependences of the traffic intensity on the approaches to the bridge crossing on the longitudinal slope and composition of the traffic flow were determined and plotted. The ratio for determining the speed of the car under the condition of the optimal functional state of the driver, which depends on the evenness, roughness, defectiveness of the coating and the speed of movement, is given. The methodology for determining the probability of trouble-free operation of highways based on the traffic intensity criterion, which characterizes the quantitative characteristics of their reliability, is given. A practical example of calculation and construction of the capacity resource function of a highway section is considered

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