Impact of Side Friction on Performance of Rural Highways in India

Abstract

Abutting land-use patterns always play an important role in the performance of a road section. Land use along rural highways in developing countries is significantly different from that in developed countries. Existence of side friction in rural highways is a common characteristic in developing countries like India. In India, substantial investment has been made to improve the performance of various categories of roads. Widening and strengthening projects have been taken up and condition of road surfaces has been improved, but travel speeds and service levels have not been improved as expected because of prevailing land-use patterns. One important factor has been the existence of side friction along rural roads in India. Roadside markets are generally found at a frequent intervals along rural highways. Interactions among fast moving vehicles, pedestrians, and slow-moving local vehicles occur in a unique and random manner. The objective of the present work is to quantify the impact of roadside friction generated by roadside markets on travel speed, capacity, and level of service (LOS) of rural highways in India. A roadside friction index (RSFI) has been developed to quantify side friction. Using data collected from three study sections, speed-flow curves were developed for various side friction levels. The k-mean cluster analysis algorithm was applied for determining threshold values for LOS. Five threshold limits for LOS are recommended for a stable flow zone considering percentage speed reduction (PSR) and volume:capacity (V∶C) ratio as measure of effectiveness. Impacts of side friction on the capacity of rural highway are also investigated.