EX ANTE HEURISTIC MEASURES OF SCHEDULE RELIABILITY

M Carey

Document Type

Journal Article

Publication Date

1999

Subject Area

operations - scheduling, operations - reliability, planning - methods, mode - mass transit

Keywords

Transit, Simulation, Schedules and scheduling, Reliability, Public transit, Mass transit, Local transit, Heuristic methods, Computer simulation, Arrivals and departures

Abstract

Measures of reliability and punctuality of scheduled public transport services are important in planning, management, operating and marketing of these services. Various methods can be used to measure reliability. Analytic methods are usually practical for only very simple structured systems. Simulation methods are very time consuming and require data which may not be available. As a result, the most widely used measures are ad hoc or heuristic. However, the assumptions and properties of these measures, and the relationships between them, are seldom discussed, hence they are discussed here. The author considers existing measures, extensions of these, and new measures. The focus here is on measures which can be used in advance, for example for estimating the reliability of proposed schedules or changes in schedules at the design stage. The author distinguishes between exogenous delays, which are beyond the influence of the scheduler (delays due to problems in engineering or operations), and knock-on delays which are affected by schedule design: both types are of interest for schedule reliability, but the latter are of more interest for measuring schedule robustness.

Comments

Transportation Research Part B Home Page: http://www.sciencedirect.com/science/journal/01912615

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