Punctra: Transit Reliability

Punctra helps you compare upcoming public-transit departures when arriving by a specific time matters.

Choose a supported agency, origin, destination, departure, arrival deadline, and buffer. Punctra combines current transit feeds with a bounded history of observed delays on the server. Each result shows the estimated chance of arriving on time, median arrival, 90th-percentile arrival, evidence count, confidence, freshness, and the largest identified risk.

Evidence stays visible. When a departure has no usable history, Punctra shows the timetable and explains that no estimate is available instead of inventing a probability.

Protect an important trip to receive a warning if its estimated reliability falls below your chosen threshold. Protected-trip watches expire automatically, and you can delete them from the Data screen at any time.

Supported live agencies at launch:

- MBTA in Boston
- King County Metro in Seattle
- Metro Transit Madison

Key features:

- Compare departure reliability against your arrival deadline
- See median and 90th-percentile arrival estimates
- Inspect evidence counts, confidence, and data freshness
- Recognize timetable-only results with no history
- Protect a trip with an optional reliability threshold
- Find the nearest supported feed using foreground location
- Delete protected-trip data inside the app

Transit data can be late, incomplete, or incorrect. Probabilities are estimates, not guarantees. Punctra is independent of the transit agencies it supports.

Punctra uses an anonymous Firebase session to protect its backend, Firebase Cloud Messaging for trip warnings, and optional foreground location only when you ask to find the nearest supported feed. Search text and recent selections stay on your device. See the privacy policy for full details.

Recent changes:
Initial release with live transit reliability estimates, evidence counts, and protected-trip alerts.