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Method

How the transit ridership figures are made

How the pages of the Public transit hub read what their publishers put out, and what that record can and cannot say. The method every topic shares — where a figure comes from, snapshots, freshness and corrections — is on the site’s methodology page.

What the National Transit Database holds

Each transit agency that reports to the Federal Transit Administration, for one report year, as two of its tables: the agency registry and the annual service table. The registry says where each agency is and what it reports. The service table gives its unlinked passenger trips and vehicle revenue miles by mode and type of service.

What a row is

A row in the registry is one agency under one state parent. An agency that reports under two parents has a row for each, and a page or a ranking shows each parent’s state. The service table adds one row per mode and type of service, and the hub sums only the annual rows, because the average-day rows count the same trips again.

Rows with no mode

Some annual rows carry no mode. They belong to agencies that report as rural reporters, and the publisher gives their trips and miles without saying which mode they are. The hub prints them apart, as their own figure, and never adds them to the moded total. The “every annual row” figure on the transit question pages is the two added together by the summary query, and nowhere else.

What a state is

A state is the agency’s address state in the registry. It is not the area the agency serves. A transit agency that runs across a state line is counted where it is registered, and the figure for a state is the agencies registered there, wherever they run.

Figures the publisher left blank

A blank is shown as not reported, never as zero. A record with a mode row that has no trips or no miles is not ranked on that measure, and the rankings say how many records were left out for that reason.

What is not on the hub yet

The four-year trend, the monthly ridership series, expenses, and the safety tables are separate pulls, one source each, and no page shows them until its pull has passed its gates. The monthly series is a separate and provisional line, and it does not reconcile with the annual table at key level, so the hub does not show one as a correction of the other.

What this data cannot show

  • A trip is a boarding, so a rider who transfers is counted once for each vehicle. The counts record trips and miles, and say nothing about why either changed.
  • A state is the agency's address state in the registry, not the area its service reaches. An agency that serves a neighboring state is counted where it is registered.
  • Rows with no mode are reported apart and are never added to the moded total, and a figure the publisher left blank is shown as not reported, never as zero.

Sources

Data retrieved