Design and control considerations for automated ground transportation systems

Abstract

Fundamental system and control problems associated with proposed automated ground transportation concepts are discussed. The problem formulation provides a systematic approach toward the synthesis and techinical evaluation of a large class and future systems employing automatically controlled single-mode or dual-mode vehicles on intracity guideway networks. Important system engineerig problems--common to some degree to all proposed concepts--are defined and the associated control requirements are discussed. Basic performance criteria, the weighted average travel time and relative safety of travel, are formulated. Tradeoffs between important system parameters are identified and their relations to performance and cost are discussed. Analysis of system operation is based upon idealized models in which perfect information and control are assumed. Upper bounds on performance are thus obtained, and the main constraints are identified. The degradation of system performance resulting from random arrivals and departures is thereafter analyzed quantitatively. Finally, control problems arising from the use of short headways are discussed. The objective of the paper is to help develop a systematic approach to the design of automated transportation systems using digital computers and modern electronic communications. It concentrates on the functional system problems of relatively simple networks, which lend themselves to direct analytical approaches and which constitute a point of departure for more complex networks.