This map shows MBTA bus positions across Boston, refreshed every 30 seconds.
Colored markers are buses running ahead or behind schedule. Green means on time. Red means very late. The marker grows with severity.
Purple pairs are bunching events — two buses on the same route that are too close together (within 100m), which means service gaps for riders behind them. *
* A bunching event may show only one purple marker instead of two. This happens because vehicle positions are currently derived from the deviation list: if a bunched bus is running on time (no deviation), its position isn't available to draw the marker. The underlying detection still works correctly.
What the numbers mean:
The stats panel (top-right) shows deviation and bunching counts.
These are not instantaneous. They represent
events that occurred in the last 3 minutes. For example,
400 deviations means 400 bus arrivals were ahead or behind
schedule in that window, not that 400 buses are late right now.
Some of those buses may already be back on time.
How the data gets here:
MBTA feed
→
Ingestion
→
Kafka
→
Analytics
→
MongoDB
→
This map