Time–space diagram revisited

Abstract

Widely used in the design and analysis of transportation systems, time–space diagrams were developed in an era of data scarcity, when it was necessary to obtain data by means of driver logs, human observers, and aerial photographs. This paper shows how time–space diagrams remain relevant today, in an era of data abundance. An application efficiently encodes the trajectories of bus GPS data in a time–space cube and uses simple geometric methods to calculate and to visualize the headways and separation of buses on a bus route. These methods are discussed in detail. How they can be used as the basis of a software package that monitors performance measures for a variety of applications is explored.