slow-zones

Finds stretches of track where trains are consistently slower than normal, then publishes them for the dashboard's Slow Zones page and the Slow Zone Bot.

Private repo

Ask in Slack for access.

Stack	Python + pandas (plain Lambda, not Chalice)
Runs on	Lambda SlowZonesLambda, daily at 10:00 UTC
Deploys	Push to main

flowchart LR
    dd["Dashboard API<br/>travel times, dwells"] --> sz["SlowZonesLambda<br/><small>daily</small>"]
    sz --> arch[("tm-mbta-performance<br/>SlowZones/ archive")]
    arch --> sz
    sz --> static[("dashboard.transitmatters.org<br/>static/slowzones/")]
    static --> site("Dashboard") & bot("Slow Zone Bot")

Good to know

• The output files are all_slow.json and delay_totals.json.
• The archive also feeds mbta-performance's travel-time benchmarks.