Search

An intensive increase in road transport, particularly individual, in recent years has led to such consequences as increased time spent on travel, the number of forced stops, traffic accidents, the occurrence of traffic jams on the road network, reducing traffic speed and a deteriorated urban road network in cities. The most effective method for solving these problems is the use of graph theory, the main characteristics of which is reliability, durability and accessibility of a free as well as loaded network. Based on their analysis the methods for network optimization are proposed. [ABSTRACT FROM AUTHOR]

General data on the network of Ukrainian highways are presented. The analysis of design methods of highway reconstruction based on the theory of traffic flows and economic calculations of its repay time is made. The relationship between traffic intensity and speed is shown by considering the theory of traffic flows. The methods, taking into account the principle of effectiveness of highway reconstruction based on its repay time, are discussed. [ABSTRACT FROM AUTHOR]

Recently, negative trends towards the environment where the system of Mass Passenger Public Transport (MPPT) operates continue to grow. Mobility and citizens' standard of living are constantly increasing. A significant increase in using private cars (level of motorization) along with all negative consequences faced under such circumstances as an increase in traffic volume, congestions, a decrease in travelling speed, a higher number of traffic accidents, greater negative influence on the environment etc. can be noticed. Th e city of Belgrade has recognized the significance of continuous research and has monitored the quality of Mass Passenger Public Transport service as well as changes that are taking place in order to influence some specific parts of transport and traffic policy in the city. Th is paper contains the benchmarking of results obtained in research and a trend towards changes in the expected and perceived quality of service (QoS) within the system of Mass Passenger Public Transport in Belgrade within the period from 2005 to 2007. [ABSTRACT FROM AUTHOR]

Traffic circles have been used in many countries all over the world. Traffic circles can be defined as intersections where traffic circulates around a center island where priority is given to the vehicles entering from branches and are designed considering weaving movements as the basic goal. Th ere are two most common capacity analysis methods for traffic circles: the method of critical gap acceptance and the method of regression analysis. Th is study explains the methods of gap acceptance and regression analysis. Ashworth and Field method is investigated and the applicability of these capacity models in Turkey is discussed. Th e obtained results have shown that both methodologies give satisfactory results; however, the existing methods should be improved (modified) considering conditions. [ABSTRACT FROM AUTHOR]

Intersections are the key components of road networks considerably aff ecting capacity. As fl ow levels and experience have increased over the years, methods and means have been developed to cope with growing demand for traffic at road junctions. Among various traffic control devices and techniques developed to cope with conflicting movements, traffic signals create artificial gaps to accommodate the impeded traffic streams. Th e majority of parameters that govern signalised intersection control and operations such as a degree of saturation, delays, queue lengths, the level of service etc. are very sensitive to saturation fl ow. Th erefore, it is essential to reliably evaluate saturation fl ow for correctly setting traffic signals to avoid unnecessary delays and conflicts. Generally, almost all guidelines support the constancy of saturation fl ow irrespective of green time duration. Th is paper presents the results of fi eld studies carried out to enable the performance of signalised intersections to be compared at diff erent green time durations. It was found that saturation fl ow decreased slightly with growing green time. Reduction corresponded to between 2 and 5 pcus/gh per second of green time. However, the analyses of the discharge rate during the successive time intervals of 6-seconds showed a substantial reduction of 10% to 13% in saturation fl ow levels aft er 36 seconds of green time compared to those relating to 6-36 seconds range. No reduction in saturation fl ow levels was detected at the sites where only green periods of 44 seconds or less were implemented. [ABSTRACT FROM AUTHOR]