Developing a method of multi-lane roundabouts capacity

Abstract

Introduction. In recent years a number of methodological and regulatory documents have been developed for public road roundabouts in the Russian Federation. In particular it was proposed to evaluate the quality of traffic management at roundabouts by the level of service measured by the average delay at roundabout entrances. The extension of the average delay criterion to the design of roundabouts requires the development of a methodology for estimating the capacity of traffic lanes at multi-lane roundabout entrances.The aim of the study. Is to develop a methodology for estimating the capacity of multi-lane roundabouts.The object of the study. Is the functioning of multilane roundabouts. Subject of the research. Are the regularities of influence of traffic volume on the values of characteristics of transport streams interaction in the conflict points of multilane roundabouts.Theoretical foundations of the research. The model for estimation of carrying capacity of multilane roundabouts based on the use of conflict points and function of acceptance of intervals is offered.Research Methodology. The video footage of multi-lane roundabouts in the cities of Bratsk, Vladivostok, Irkutsk, Lipetsk, Nakhodka, Orenburg, Petrozavodsk and Pskov was processed. On each lane of the circular carriageway, intervals in the flow, measured between the front bumpers of vehicles, were recorded. The accepted and rejected headways were registered, as well as the number of vehicles using accepted intervals. The determination of the values of critical headways and follow-up time was performed using the Siegloch’s method based on linear regression.Results. A model for estimating capacity at the entrance to a multi-lane roundabout was validated. The values of critical intervals, queuing intervals of each of the entrance lanes to 2-lane and 3-lane roundabouts were determined. The values of the minimum headways in the flows moving on the circular carriageway are determined, also the dependences of the influence of traffic intensity on the free share of the traffic flow are established.

Keywords

• multi-lane roundabouts
• capacity
• conflict points
• gap acceptance function
• critical headway
• follow up time