The paper is a result of a research work concerning the development of an environmentally friendly transport system - Project EMITRANSYS. The publication contains the issues of shaping the transport system, where important factor due to the aspect of sustainable development is including the external costs in transport activity. This paper presents a mathematical model of the distribution of the traffic flow in the transport network. The paper presents selected aspects of the problem of multi-variant distribution of the traffic stream on the network transport for defined scenarios for the transport system development. Traffic distribution on the network has been made due to the criterion function – external cost connected with air pollution. The paper presents modal split of traffic ecological flow for chosen scenarios of the development domestic transport system. Key words: distribution of traffic on the network,

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The article presents an approach to assessing the reliability of logistics processes implemented in supply chains in terms of time losses resulting from the selection of a variant of material flows in the supply chain. In order to define this indicator, a mathematical model of the supply chain has been developed, i.e. the parameters of the research problem, the decision variables, the constraints and the evaluation criteria. The method of evaluating the reliability of the system is presented in diagram form. The algorithm was verified based on experimental data. In order to evaluate the reliability of the logistic processes for the sample supply chain, a simulation model was developed that determines the time losses in the points and linear elements of the examined chain. Time losses are dictated by traffic delays resulting from traffic congestion on particular sections of the route and road junctions and delays in point elements in the supply chain.

This paper discusses selected environmental and technological issues of routing freight vehicles in urban areas. The conditions of organizing distribution minimizing not only realization time but also the emission of harmful components of exhaust gases are described. Time-dependant traffic conditions characteristic for densely populated urban areas are defined and discussed according to ecological aspects. Theoretical information about CO 2 emission in urban conditions are gathered and used to formulate the base of mathematical model of a Time-Dependant Vehicle Routing Problem with emission criteria function, as a version of Capacitated Vehicle Routing Problem.The model comprises selected characteristics of urban transport infrastructure such as distances, speed limits, zones, or the effect of rush hours. It allows considering different types of vehicles according to the task requirements and emission characteristics, and changing traffic conditions.The model is implemented onto a representation of a real transport network and solved for given data with two step-heuristics basing on a modified A-star algorithm and genetic programming. Appropriate results, future research directions and other potential uses are presented and discussed.

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