Citation

Savage J. Transp. Res. Rec. 1997; 1608: 6-16.

Copyright

(Copyright © 1997, Transportation Research Board, National Research Council, National Academy of Sciences USA, Publisher SAGE Publishing)

DOI

10.3141/1608-02

PMID

unavailable

Abstract

Transportation service level measurements have been commonly used and accepted for highway systems, but similar service measures for ferry systems are less common, especially from the users' point of view. An approach to measuring ferry route level of service is described that allows comparisons among ferry routes and between ferries and alternate modes such as highways (i.e., drive-around choices) and transit. The recommended approach focuses on excess user waiting times (excess delay) by mode (automobile, registered carpool or vanpool, bus, truck, and walk-on passenger), combined with calibrated relationships between volume-to-capacity (V/C) ratio and user delays for forecasting purposes. Data on waiting times for vehicles in the queues were collected on all ferry routes serviced by Washington State Ferries, and an extensive statistical analysis was performed to compute the relationships between V/C ratios and excess waiting times. Excess delay was defined as the waiting time for missed vessel sailings due to overloads, if any, after a ferry patron has arrived at the dock. User delays were expressed in two forms: absolute number of minutes of waiting time, and the number of boat sailings missed before boarding a ferry. The "boat wait" concept was introduced to differentiate between excess delays caused by congestion that prevents a driver from boarding the next ferry, and delays related to the amount of service provided on a route as reflected in the headways between vessels.

Language: en