Artūras Keršys

Assessment of bicycle–car accidents under four different types of collision

Bicycle riders are among the highest risk group in traffic. A cyclist simulation study captured kinematics and injuries to legs, pelvis, neck, and head for one human body size. We analyzed the number of parameters (forces acting on left and right tibia, head injury criterion, neck tensile force, neck shear force, and pelvic acceleration) for each of the four different cases: bicyclist ride out—residential driveway, motorist overtaking—undetected bicyclist, bicyclist left turn—same direction, and bicyclist right turn—opposite direction. The comparison of simulation outcomes for leg injuries with official hospital records has shown a very good correlation in terms of injury severity prediction. This study concludes that if countermeasures to prevent fatal cyclist injury in car impacts were to be concentrated on mitigating head and neck impact to the windscreen of the car, a dominant share of fatal cyclist crashes and severe traumatic head injury cases at collision speeds exceeding 40 km/h could be prevented.

Research of Congestions in Urban Transport Network Using Cellular Automation Model

Abstract The growing demand for transport and communication services leads to more and more important, traffic related and closely associated problems, especially in the city centre, such as traffic congestion, air pollution, noise and some others. When modelling traffic flows in the Kaunas city centre, the simulation models of crossroads were created based on the principle of cellular automaton model, taking into consideration such relevant traffic indicators as the average speed of traffic flow in different streets, traffic intensity, congestions and distributed flows. Operation of cellular automaton model is associated with the improved approach of further vehicle model. Modelling of microscopic traffic flows is based on the brake light–cellular automaton (BL–CA) model. Random functions were made discreet and autocorrelation values of these functions were calculated in this work. Fundamental macroscopic traffic characteristics were obtained. Numerical dependences of the average traffic speed and traffi...

Research of the influence of tire hydroplaning on directional stability of vehicle

AbstractVehicle use is inherently linked to the risks. While transport means are being constantly improved, active and passive safety issues appeared to be more and more complex what makes experimental testing and numerical modelling problems of safety – sensitive structures considerably actual. In case of hydroplaning phenomenon to keep the vehicles stable direction its movement becomes more difficult. Selection of the safe speed is one of the main objectives in order to ensure greater traffic safety and reduce the possibility of an accident. The aspects of tire simulation by finite element method were revealed and analysis of the impact of a vehicles speed on the appearance of hydroplaning process was performed. The peculiarities of Euler–Lagrange formulation of dynamical problems and modelling of fluid – structure interaction by finite element method are presented in the research. The article describes preliminary models developed using the PATRAN and DYTRAN software packages. On the basis of these m...

Investigation of asphalt texture roughness on friction evolution for wheeled vehicles

AbstractNovelty of the research lies in understanding the safety advantages of asphalt made using advanced pavement design process – compact asphalt pavement installation. Variation of tyre–road friction coefficient for this type of pavement design is new and little-studied phenomenon. The present study focuses on the research into tyre–pavement interaction on dry asphalt pavement surfaces to quantify the effect of microprofile on vehicle performance in establishing its braking conditions. The data on a number of different indications (vehicle speed, adhesion coefficients calculated on the basis of braking and friction forces, maximum adhesion coefficient mmax and its ‘minimum’ value m100%) and measurement results generated using SRT-4 device for investigation of two road stretches at intervals of 100 m are presented in this paper. The interdependence analysis of statistical variables mmax and m100% has also been presented to exhibit the use of the method. Following statistical parameters are taken into a...

City transport analysis using the General Motors (GM) microscopic model

AbstractAutomobile, bus and trolleybus traffic flow in urban areas is increasing because of transport growth and continuous demand for it. The developing economy and changing social status of the population increases the need for mobility. Therefore, urban transport flow is increasing, resulting in traffic congestions, since the street network throughput in practice does not change. The negative effect caused by the traffic congestions is most notable in the largest cities, where traffic density is relatively high, with characteristically low and often variable speed (acceleration and deceleration). We present in this paper a modification of General Motors (GM) traffic flow simulation model in order to identify best possible prerequisites for traffic flow management. The forecasting model employs the following independent variables: vehicle movement speeds, service time (traffic light signal duration), traffic flow intensity, average service frequencies, and the lengths of formed queues. By specifying different functional forms of response time we propose a generalized methodology for traffic management and obtain a theory, which is demonstrated in this paper through both numerical simulation and theoretical analyses. The developed simulation model based on GM’s car following model shows good correlation to the field data. To this end, this paper presents a designed assessment method for the short-term congestion, expressing the negative impact of the transport system in monetary units.

SEARCH OF THE ROUTE IN THE NETWORK OF PUBLIC COMMUNICATION USING A LINEAR SEQUENCE METHOD

Abstract The problem of searching the route in the network of public communication is being investigated in the article. A new line sequence method working on the base of a real network model is created for route research in transport communication network and the problem solution. Having analysed a modeling peculiarity of passenger behavior choosing the route, the route evaluation and comparison of the resistance function, including the factors for the route chaise are defined: traveling time, cost and comfort (number of changes). On the base of the mathematic calculation results of public transport communication a part model was determined. It offered the method of the work that can be used for the solution of the examined problem and integrated into the prognosis models of communication processes.