Level of service of urban roads based on users' perception

Level of service (LOS) is a qualitative measure of traffic flow from the users' perspectives. This paper presents a new methodology to find LOS of urban roads by taking users' perceptions and analyzing them through fuzzy set theory. Speed, volume and acceleration noise (defined as the standard deviation of accelerations) are taken as the evaluating criteria, The six categories of LOS A to F of the Highway Capacity Manual are assigned linguistic terms. The users have been divided into two age groups. Their perceptions, recorded through primary surveys, have been used to establish membership functions for different fuzzy sets and to arrive at importance factors assigned to them. Four important corridors of movement in the Metropolitan City of Madras formed the backdrop of the study.