BRT Corridor Capacity Calculator

Peak Hourly Capacity is the product of two inputs only: how many buses per hour the Headway allows (3,600 seconds divided by Headway, rounded down) and how many riders each bus holds (Bus Capacity). Both capacity figures are per direction — the standard transit-planning unit is passengers per hour per direction (pphpd), so double them for a two-way corridor total. Neither Station Spacing nor Route Length has any effect on this figure — they instead drive Station Count and End-to-End Travel Time, which are calculated separately. Bus Capacity is a direct linear multiplier on Peak Hourly Capacity, while Headway acts through a floor-rounded inverse (buses-per-hour is 3,600 divided by Headway, rounded down) that gets sharply more sensitive as Headway approaches its 30-second minimum — at that extreme, buses-per-hour hits 120, four times the 30 buses per hour a default 120-second headway produces. That 120 figure is a throughput ceiling, not an operable service plan: the ITDP BRT Planning Guide puts one-lane, one-docking-bay saturation at about 60 buses per hour, above which bunching becomes unacceptable, so anything below a 60-second headway here presumes passing lanes and multiple sub-stops at every station.

Note also that Peak Hourly Capacity multiplies buses-per-hour by the full Bus Capacity, with no load factor and no peak-hour factor — it is the theoretical maximum if every bus in the peak hour arrives exactly full, and real planning practice discounts it by roughly 10-25%. Which of the two inputs swings the result further depends on where you start from in each one's declared range. Daily Capacity extends the peak figure across an assumed 16-hour operating day using a fixed load-factor curve — 4 peak hours at full capacity, 4 shoulder hours at 60%, and 8 off-peak hours at 30% — rather than any ridership data you provide, so it always scales as a constant multiple of Peak Hourly Capacity. Travel Time is simply Route Length divided by the Average Operating Speed you enter, so it does not model dwell time at each station, traffic signal priority, or how closely spaced stops slow a route down — those effects have to be baked into the speed figure you supply. Reported US BRT operating speeds (dwell included) cluster around 10-13 mph for street-running lines; only grade-separated busways such as Pittsburgh's East Busway reach the high twenties, so a default of 13 mph is a much safer planning assumption than the free-flow speed of the vehicles.