Lateral Placement Characteristics of U-Turning Vehicles: A Statistical Investigation

Abstract

The present study is carried out to comprehend the lateral placement characteristics of U-turning vehicle by collecting field data from 11 different median openings across India. Videography technique was used for data collection. A distribution fitting toolbox of MATLAB is used to fit the lateral placement data into statistical distribution and it is found that the collected lateral placement data of six test sections agreed to gamma distribution and five test sections were expressed with normal distribution. The lateral placement of U-turning vehicle moves away from the median side when the width of the road increases. Furthermore, from ANOVA test results, it is found that lateral placement of U-turning vehicles differs significantly due to the presence of kerb or shoulder. Subsequently, it is observed that at low hourly approaching through traffic volume (ATTV), the lateral placement of U-turning vehicles is skewed towards the kerbside of the carriageway and as the volume increases, lateral placement shifts towards the median side. Subsequently, mathematical models have been developed for different category of U-turning vehicles with varying ATTV. The developed models will be helpful for estimating conflicting traffic volume at median opening and proper estimation of conflicting traffic volume will result in better estimation of U-turn capacity at median opening. Furthermore, study of lateral placement will also be helpful for proposing a geometrical augmentation at median opening for reducing traffic congestion and for enhancing the level of service and safety.