Regression model for entry capacity of a roundabout under mixed traffic condition – an Indian case study

Abstract

This paper presents a regression model which is developed to estimate entry capacity of an approach on a roundabout for Indian traffic conditions. The entry capacity of an approach on a roundabout is expected to depend on the circulating traffic flow in front of that approach and the safe opportunity for vehicles entering that flow. The relationship between entry capacity and circulating traffic flow is found to be negative exponential i.e. the entry capacity decreases exponentially with an increase in the circulating traffic flow. The analysis also indicated that the widths of circulating roadways and central island diameters have a significant influence on the entry capacity. The circulating traffic flow versus entry capacity charts were made with the purpose of comparing the results of the proposed model with the existing models available in the literature, namely Jordanian, Malaysian, and Indian. The comparison indicated that the proposed entry capacity model gave the highest entry capacity, whereas the Malaysian model gave the lowest entry capacity. The results of the proposed model have shown very good relationship with the field entry flow data, as compared to other models. Hence, this model is suggested to estimate entry capacity on roundabouts under similar varied traffic flow conditions in developing countries.

Keywords:

• Roundabout
• mixed traffic
• entry capacity
• regression analysis
• India