Modelling follow-up time at a single-lane roundabout
The follow-up time is an important parameter for estimating the entry capacity of roundabouts. However, its variability and contributing factors have long been ignored in the literature. In this study, 171 follow-up samples and contributing factors (traffic volume, vehicle position, waiting vehicles behind, vehicle type, and drivers'gender) are collected at a roundabout in Pacific Pines, Australia. It is found that the follow-up time is indeed significantly affected by traffic volume, waiting vehicles behind, vehicle type, and drivers'gender. In order to establish the relationship between follow-up time and its contributing factors, an inverse Gaussian regression model is further developed. This relationship could be applied to estimate the entry capacities by taking into account the variability of follow-up samples. According to the model, the traffic volume and vehicle types are the most important contributing factors. 2014 American Society of Civil Engineers.