J. Edward Anderson

A comprehensive method for calculating and measuring Dependability of Personal Rapid Transit systems is derived and compared with the more common measure called Availability. Availability is the percentage of all revenue trips that are completed without interruption. It does not take into account the duration of delays of the passengers because of the difficulty of gathering the necessary information in conventional transit systems. In PRT systems, vehicle-hours of travel and of delay relate in a statistically simple way to person-hours of travel and of delay. Therefore, in such systems, it is practical to use the performance measure called Dependability that takes into account the inconvenience of people as a result of delays. To form a bridge to present practice, it is recommended that both measures be calculated and compared in forthcoming PRT systems. With today's computer systems, this is easily accomplished.