Public Transit Operations and Systems
Public Transit Operations and Systems
This domain tests whether you can read a transit system as a production process - vehicles, operators, and service hours converted into scheduled service - and whether you know how that service is measured, costed, and reported. Questions cluster around schedule mechanics (cycle time, layover, peak vehicles), service-quality metrics, and the National Transit Database (NTD) definitions that govern federal reporting.
Schedule arithmetic
- Headway is the planned interval between vehicles at a timepoint; span is the hours of service offered.
- Cycle time = running time outbound + running time inbound + layover/recovery at each terminal. Recovery protects on-time performance; it is part of the cycle, not slack to trim when a schedule runs long.
- Peak vehicle requirement (PVR) = cycle time ÷ headway, rounded up.
- Blocks and pieces of work assign vehicles and operators; a tripper covers one peak only and is a common source of split-shift and overtime questions.
NTD and performance definitions
- Unlinked passenger trips (UPT) count boardings; a journey with a transfer counts twice. Passenger miles weight each trip by distance travelled.
- Vehicle revenue miles/hours exclude deadhead, pull-in/pull-out, maintenance and training movements.
- On-time performance is set by agency policy, commonly "no more than 1 minute early and 5 minutes late" at timepoints.
- Farebox recovery = fare revenue ÷ operating cost; cost per vehicle revenue hour is the usual efficiency benchmark.
Worked example
Route 12 runs 22 minutes each way with 5 minutes of recovery at each terminal; peak headway is 10 minutes. Cycle = 22 + 22 + 5 + 5 = 54 minutes. PVR = 54 ÷ 10 = 5.4, rounded up to 6 buses. If each bus is scheduled for 8 revenue hours, the peak contributes 48 vehicle revenue hours; the deadhead from the garage to the terminal must not be counted in that figure, or NTD reporting and cost per hour will both be wrong.
Traps that cost marks
- Rounding PVR down - a fractional vehicle is a real bus.
- Reporting total vehicle hours rather than revenue hours to the NTD.
- Treating layover as waste; cutting it pushes delay onto later trips and erodes reliability.
- Confusing UPT with passenger miles in ridership or productivity questions.
- Assuming higher frequency always lowers cost per trip: crew, vehicle, and maintenance costs step up in whole units.