Optimal bus line length

The length of a transit line has received little attention in current transport literature. This paper develops analytical models of bus line length. The models are derived using the following steps: (1) Assume a continuous spatial interaction model in a transport corridor, where Txy is the number of trips between x and y, and are parameters. (2) Derive the cost of operation as a function of line length. (3) Derive travel demand (passenger-trips and passenger-km). (4) Derive total revenue under flat and graduated fare systems as functions of travel demand and line length. (5) Find the optimum line length for operator. A case study is presented to examine the model parameters. The sensitivities of the values to changes in and are examined. Bus line lengths in various urban structures (in term of population and employment distribution) are discussed in the paper.