Desk
Quality & Compliance
Validation, conformance, feed health, and reporting such as NTD and SB125.
04entries
On this desk
Explainers
Roundup
August 2026 roundup: the NTD goes public, MDS 2.1 ships, and alerts get a clock
What moved on the transportation data layer from mid-July to early August 2026: FTA's Transit Moves America dashboard, a federal question about whether real-time data counts as service quality, the MDS 2.1 release, and two new GTFS-Realtime alert fields.
Explainer
Bus bunching and headway: why three arrive at once
Three buses arriving nose to tail is not bad luck. It is a feedback loop in frequent service, where a late bus falls further behind and the one behind it catches up. Here is the mechanism, why agencies measure headway instead of schedule, and what they do about it.
Explainer
Ghost buses: why the app shows a bus that never comes
A ghost bus is a prediction with no vehicle behind it. Here is how a transit app generates one, the four ways it happens, and how Chicago drove its rate down.
Explainer
What the National Transit Database actually holds
The NTD is the federal record of US public transit: who rides, what it costs, and who has to report. Here is what it holds, who files it, and how to pull the numbers yourself.