Critical street links for demand responsive feeder transit services

This paper presents a methodology to identify and locate critical links in a grid street network system for feeder transit services. A 'critical' link can be defined as a link that-when eliminated from or appended to an existing network-would cause the largest change in the network connectivity and consequently in the transit performance. The most significant contribution of this study is to present a simple analytical approach to locating the critical link(s) for a grid street network system of any size with uniform passenger demand across the service area. The distance between demands points have been used as the basic measure of impedance in the final derived closed-form equations. Easily computable formulas for identifying the critical links have been validated by simulation analyses with the street network system from the City of St. Joseph, Missouri. Useful insights from the analytical derivations and simulation results indicate a monotonic decrease in link criticality when moving from the centrally located links to those located at the periphery in a grid street network system.