Calculation parameters of total transport congestion costs in urban road network

Abstract

The extent of external transport congestion costs is described by the economic welfare theory as deadweight loss, which results from ineffective use of transport infrastructure. Exact calculations are barely possible according to this theory and are thus often made by engineering methods, where instead of defining the extent of social welfare changes (as a consequence of modified equilibrium between transport supply and demand) functions are used which define costs of lost time and operational costs as: i) speed-flow relationships, ii) value of time, iii) other operational costs and iv) unit cost functions. The implementation of this method in the interurban road network is successful and gives good results yet this is not the case when the method is implemented in the urban road network. The set of required data for the calculation (number of lines for each road segment, number of vehicles by category and time for each road segment, values of time by categories of transport, etc.) is unavailable in many cases for urban transport networks. This is the reason for implementing a modified engineering approach where the set of required data is reduced and supplemented by the set of parameters which lead to the same result. The article deals with the set of parameters and correction factors which supplement originally demanded data.