Performance evaluation of urban corridors using the speed profile data of automobiles

Abstract

The macroscopic traffic flow parameters derived as the aggregate outcome of traffic conditions over a period appears inadequate for capturing the variations in quality of service experienced by the users (TRB, 2010). Hence, the objective of the study reported here is to develop the Automobile Level of Service (ALOS) criteria for the heterogeneous two-lane undivided urban corridors, considering the manoeuvrability of individual automobiles. The speed profiles of the motorised two-wheelers, three-wheelers, and cars were collected from the urban corridors of Kerala, India, using GPS based mobile application. From the speed profile data, the speed and time variation characteristics were studied in detail. The microscopic parameters depicting the quality of travel were identified as speed ratio (SR), coefficient of variation of speed (CV), and congestion index (CI). Conventional linear regression models were developed with a 95% confidence interval for predicting the quality measures and validated with 20% of the collected data. K-means clustering technique was applied to define the threshold values of the ALOS classes. Six specific ALOS classes were identified and validated with silhouette coefficient values. The criterion values estimated for the heterogeneous traffic condition were significantly differing from the homogeneous traffic values given by HCM 2010. Hence this method can be used for assessing the performance of heterogeneous two-lane undivided urban corridors from the individual drivers’ point of view.