Realtime reliability.

1577 feed records meet the comparison contract, but none has a realtime monitor observation yet.

In plain words: a realtime feed is only useful if it is actually up and current. This tracks whether each monitored feed responded when we checked and how far behind real time it was. An agency that publishes no realtime feed is not counted here and is never penalized for it.

Reliability is the share of monitor runs the feed responded to, over the recorded window; freshness is the median header lag. It never changes a grade. The same data is at the realtime API (realtime.json). Sampling is periodic, not continuous, so this is a reliability signal, not a complete uptime log. The directory contains 2009 published feed records; 1577 meet rubric 1.3, scoring profile gtfs-scorecard-1.3, MobilityData gtfs-validator 8.0.1, reader archive profile raw-v1, and measured categories Correctness, Freshness, Rider experience, and 0 have realtime observations used here.