Deriving capacity and level-of-service thresholds for intercity expressways in India

The knowledge of roadway capacity and level-of-service (LOS) are important for the effective planning, design, analysis, and operation of a roadway network. There is a limited body-of-knowledge available about highway capacity and LOS of intercity expressways in Asian countries, including India, where traffic composition and driver behavior are considerably different from that of the developed world. The primary objectives of the paper are to estimate capacity and to propose a new methodology of developing LOS thresholds for such intercity expressways. A microscopic traffic simulation model was developed using VISSIM and was calibrated and validated using real-world vehicular trajectory data. The LOS thresholds are then established using k-means clustering technique and further cross-validated statistically observing change in slopes of plots explaining speed–flow and speed–density variations. The capacity and LOS methods proposed in this paper are generic and should be applicable to other Asia-Pacific countries with heterogeneous traffic conditions.