Alerts overview

The Alert mechanism is highly versatile and provides contextual information to transit users for events that happen in the network. In particular, it informs users of the following:

• Cancellation of routes, network, stops, and trips using NO_SERVICE in effect field
• Transit announcements and notices with no effect on routing. For example:
  • On-the-fly addition or reduction of trips
  • Detours
  • Stop closures or movements

For more information, reference the GTFS documentation. 

Related resources

Recommended guidelines for providing an Alert:

• How to select an entity using Alert
• Cancel trips with Alert
• How announcements are ordered in Google Maps
• Categorize & display Alerts