Evaluating Operational Performance of Intersections Using SIDRA

Prakash Ranjitkar,Amin Shahin,Fasihullah Shirwali

doi:10.2174/1874447801408010050

Abstract

Traffic congestion has significant social, economic and environmental costs associated with it. Efficiency of intersections contributes significantly towards the efficiency of whole urban road networks as they are the main bottlenecks in the system. This paper presents a comparative analysis of the operational efficiency of priority controlled, roundabout and signalised intersections under a range of traffic conditions with different volume and turning ratios using SIDRA software. We used three measures to represent the operational efficiency namely: intersection capacity, average delay and total emissions. The analysis revealed strengths and weaknesses of each intersection types under a range of demand and traffic conditions. At low traffic demand, priority controlled intersections outperformed the other two forms of intersection control. At moderate traffic demand, roundabout performed the best while at high traffic demand, signalised intersections performed the best.

Highlights

Intersection design is a complex process where factors related to operational efficiency such as capacity, delay and emissions are an important consideration along with safety features and geometrical constraints
This paper reports an investigation conducted on the operational efficiency of three different intersection types namely priority controlled intersection, unsignalised roundabout and signalised intersection using SIDRA acronymed for Signalised & Unsignalised Intersection Design and Research Aid [16]
The efficiency of intersections under different traffic and control conditions was measured based on three important measures of effectiveness (MOE) extracted from SIDRA output results namely intersection capacity, average delay (s/veh) and total emissions

Summary

Introduction

Intersection design is a complex process where factors related to operational efficiency such as capacity, delay and emissions are an important consideration along with safety features and geometrical constraints. Chou and Nichols (2014) evaluated the performance of an unconventional intersection type called “triangabout” as an alternative form of intersection for nonthrough arterial movement They reported based on their case study that delay was reduced by 50% and number of conflict points by 34% compared to the existing configuration [11]. Chaudhry and Ranjitkar (2013) found that, the fundamental assumption of traffic signal design, a constant saturation flow rate, is not realistic when compared with field data [14] They proposed new models to represent queue discharge behaviour at stop line and derived the respective formulations for capacity, cycle time and green time. Sinha et al (2013) proposed a more futuristic approach to control traffic at intersections, which they termed as “virtual traffic lights+” [15]

Methods

Results

Conclusion