Glossary · approach
Frequency Setting
Operational sub-problem of determining how often each transit line is served (e.g., one bus every 6, 10, 20 minutes) per time band, based on demand profile, available fleet and target service quality.
Frequency Setting ProblemFSPService Frequency SettingTransit Frequency PlanningBus Frequency Allocation
Frequency Setting Problem (FSP) is the operational sub-problem in the public-transport planning hierarchy: for each line, how often a vehicle is dispatched per time band (morning peak 07:00-09:00, mid-day, afternoon peak, evening, night) — for example one bus every 6, 10 or 20 minutes — subject to per-band demand profile (OD matrix, load factor), available fleet (total bus count + maintenance windows) and target service quality (passenger wait time, load-factor cap). Solution approaches: **analytical** — assuming Poisson passenger arrivals, mean wait = 1/(2×frequency) (square-root law / classical wait formula), with frequency proportional to the square root of demand intensity; **MIP** — multi-objective optimisation over line × time-band × frequency variables (passenger wait + operating cost). Canonical reference Ceder and Wilson (1986); textbook Ceder (2007); periodic linkage Schöbel (2012); modern survey Ibarra-Rojas-Delgado-Giesen-Munoz (2015). It sits above transit network design and below timetabling and vehicle scheduling in the planning hierarchy.
Örnek
A metropolitan operator runs 80 bus lines; the FSP solution pulls the average peak frequency from 12 minutes to 8 minutes and softens off-peak from 25 to 18 minutes; passenger wait time drops 25% on average while operating cost grows 5% — the Pareto trade-off is presented to the decision board.