Group Gap Acceptance: A New Method to Analyze Driver Behavior and Estimate the Critical Gap at Multilane Roundabouts

Khaled Shaaban,Hassan Hamad

doi:10.1155/2018/1350679

Abstract

The operations of multilane roundabouts, especially three-lane roundabouts, are unique and more complicated than any other type of roundabouts. This study aims to analyze driver behavior and estimate the critical gap at three-lane roundabouts. Video data were collected at two roundabouts. The analysis identified a pattern of group gap acceptance, where vehicles entering the roundabout from different lanes moved in groups during the same gap. In this case, the decision of vehicles entering from outside lanes greatly depended on the gap acceptance decision of vehicles in the inside lane. Analysis showed that the vast majority of the vehicles accept the gap in groups and the critical gap was estimated accordingly. The study provides a new explanation for the operation at multilane roundabouts. The use of this simple method is recommended when estimating critical gaps for multilane roundabouts.

Highlights

Roundabouts are popular in many countries, especially in the case of lower volumes when compared to signalized intersections as they reduce queuing and delays at the approaches
Roundabout capacity is greatly affected by the gap acceptance behavior of drivers
The Highway Capacity Manual (HCM) provides a method to calculate the capacity of roundabouts, and it involves a number of inputs

Summary

Introduction

Roundabouts are popular in many countries, especially in the case of lower volumes when compared to signalized intersections as they reduce queuing and delays at the approaches. The decision making in most cases depends on the driver’s behavior. Roundabout capacity is greatly affected by the gap acceptance behavior of drivers. One of the main inputs is the critical gap [1]. This value is used in the capacity model to estimate the capacity of existing facilities without the need to perform field measurements, assess the level of service, and predict the capacity at future locations. This value is needed in simulation and traffic modeling of roundabouts for design and research projects

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Conclusion