Raimundas Junevičius

Mathematical modelling of network traffic flow

Abstract The article describes mathematical models of traffic flows to initiate different traffic flow processes. Separate elements of traffic flow models are made in a way to be connected together to get a single complex model. A model of straight road with different boundary conditions is presented as a separate part of the network traffic flow model. First testing is conducted in case the final point of the whole modelled traffic line is closed and no output from that point is possible. The second test is performed when a constant value of traffic flow speed and traffic flow rate is entered. Mathematical simulation is carried out and the obtained results are listed.

Use of steel slags in automobile road construction

Abstract Building and, especially, reconstruction and repairs of highways, call for the development of stone materials manufacturing industry. Increasing need for stone materials may be satisfied by a wide use of industrial waste and secondary resources. In road building, slag of ferrous and nonferrous metallurgy is one of the most popular wastes which are increasingly widespread with every year. Such slag is a valuable raw material for preparation of macadam materials and mineral binders serving as a base for asphalt concrete mixtures and manufacturing of cement emulsions, which are widely used in road paving. The research focused on the use of different types of slag in road construction in Ukraine. Possibilities of using crushed rock and sand as recrement slag of different production for preparation of asphalt concrete and cement mixtures to be used for road-base was studied, as well as the use of slag materials for construction of lower category roads. In the given work, the opportunity to recycle ele...

Determination of traffic flow parameters in different traffic flow interaction cases

Abstract Modelling of straight road section consisting of one traffic line gives the opportunity to simulate “follow the car” system. In general it looks like a line of vehicles, going one after another. Kinetic theory, used in this paper describes traffic flow system as a straight unbroken line with limited flow speed and concentration. Such model also gives the opportunity to derive traffic lines intersections. For example, intersection could be derived like a point with traffic lines coming and outgoing from this point by only changing boundary conditions. Mathematical model is built using characteristic method.

Modelling of Internal Combustion Engines’ Emission Through the Use of Traffic Flow Mathematical Models

Abstract Road traffic flows on a straight road segment are modelled in this article. The mathematical model of traffic flows has been constructed by using the method of lumped parameters. CO2, CO, CH, NOx, PM regression equations of internal combustion engines’ (ICE) emission has been developed. The accuracy of regression equations is 0.98÷0.99. The article presents assumptions for constructing the mathematical model, description of the mathematical model and gives simulation results. Traffic flow parameters, such as traffic flow concentration and traffic flow speed are presented as modelling results. ICE emission depending on the concentration and traffic flow speed are presented as well.

INVESTIGATION OF TRAFFIC FLOW DYNAMIC PROCESSES USING DISCRETE MODEL

Modelling the process of traffic flow was previously studied from different points of view and different mathematical methods where used to describe the same process. All authors have an agreement on basic traffic flow parameters like, traffic flow density, traffic flow rate or the average speed of traffic flow. Besides, a lot of different investigations into the use of traffic flow models to deal with various problems of engineering are carried out. A comparison of different continuum models has drawn that a number of scientific works were based on fluid dynamic theory and gas kinetic traffic flow theory. The kinetic traffic flow theory is used in ‘microscopic’ or “macroscopic”, traffic flow models. The kinetic traffic flow theory is used in Flotterod G., Nagel K., Ging A., Li L., Li-qun X., Prigogine I., Herman R. works where various approaches to the similar method are discussed. The ‘macroscopic’ theory of traffic flows also can be developed as the hydrodynamic theory of fluids that was first introduced by Lighthill-Whitham and Richards’s model. Plenty of traffic flow models are based on car–following theories supported by the analogues to Newton’s equation for each individual vehicle interacting in a system of vehicles on the road. Different forms of the equation of motion give different versions of car–following models. This work presents research of traffic flow dynamic processes, as nonlinear dynamic system, by using a discrete model of traffic flow (DMTF). The main variables in DMTF are traffic flow density and speed. DMTF can be used to describe various traffic flow situations in the roads. The mathematical simulation of traffic flow is made when constant value of traffic flow speed and traffic flow rate is entered. Numerical results of traffic flow dynamics are obtained.

Dynamic processes of the retrofited rear suspension of the vehicle

Abstract The main aim of the investigation is to design rear suspension and to improve the dynamic characteristics of the vehicle. Three types of rear suspensions that consist of a leaf spring, a hydraulic and a pneumatic damper, an air spring are designed. The dynamic models of the quarter car with these rear suspensions are presented. Random disturbance of particular road surface is played back by using a spectral density and Monte Carlo method. Natural frequencies of rear suspension are presented. The dependence of standard deviations of the first, the second and the third derivates of particular random displacements on the vehicle speed is obtained. Dynamic characteristics of three rear suspensions are compared and the best rear suspension is determined.

Economic and Social Modelling of Urban Traffic Controlling

Abstract Road traffic flows in intersections in inner city environment are modeled in this article. Cost of CO 2 , CO, CH, NOx, PM and value of travel time have been used in order to estimate the economical and social costs arising at the intersections. The article presents assumptions for constructing the mathematical model. It describes the mathematical model and gives simulation results. Traffic flow parameters, as traffic flow concentration and traffic flow speed are presented as based on real traffic data. Different controlling policies are demonstrated.