Influence of Selected Vehicle Maneuvers on Reduction of the Urban Roads Capacity

Jan Celko,Matus Kovac,Kristina Huszarova

doi:10.26552/com.c.2019.4.81-89

Abstract

Capacity assessment of urban roads according to Slovak standard does not sufficiently take into account the influence of vehicle maneuvers on road section performance between the two intersections. This research analyzed turning relations on selected urban road intersections and the influence of right turn and left turn on major stream speed changes. For the purpose of determining the influence of the right turn on decrease in capacity, measurements were carried out at 7 uncontrolled intersections with curve radius ranging from 6 to 30m. To determine the influence of the left turn on the capacity of urban road a critical gap was evaluated, using the Raff’s, method, based on the analysis of accepted and rejected gaps in the major traffic stream, which was one of the main inputs for simulations. The findings were used to determine the influence of selected maneuvers on the road capacity, which led to a proposal for reduction coefficients based on computational analysis performed using simulations in PTV VISSIM.

Highlights

Influence of the turning maneuvers at simple intersections and parking spaces on the reduction of the capacity of urban roads has not received much attention
The effect of the left turns to the decreasing of the capacity of simple intersections is determined in the Slovak Standard without the influence of opposite traffic flow intensity
The analysis of results shows that the right turn per se does not significantly influence the decrease in the capacity of urban road as it is considered by the Slovak standard [17]

Summary

Introduction

Influence of the turning maneuvers at simple intersections and parking spaces on the reduction of the capacity of urban roads has not received much attention. Authors of [7] dealt with an analysis and modelling of turning relations and their influence on the intersection capacity in urban intersections in China They generally focused on two types of crossing behaviors. Researchers in [9] simulated the turning relations using the VISSIM Their analysis of turning was predominantly based on the Harders model, they determined the base critical gaps for different types of movement on unsignalized intersections (Table 1). The methodology of collection, selection and analysis of data regarding the characteristics of traffic flow and observations of actual intersections in the city of Zilina were performed as a part of research activities conducted at the authors institution The aim of this part was to determinate the influence of selected maneuvers on urban road capacity. To verify the theoretical calculations, measurements were used as input into a simulation model which was used to further specify obtained results

Right turns

Left turns

Findings

Conclusion