Example of an Alerts feed

header {
  gtfs_realtime_version: "1.0"
  incrementality: FULL_DATASET
  timestamp: 1284457468
}
entity {
  id: "0"
  alert {
    active_period {
      start: 1284457468
      end: 1284468072
    }
    informed_entity {
      route_id: "219"
    }
    informed_entity {
      stop_id: "16230"
    }
    cause: CONSTRUCTION
    effect: DETOUR
    url {
      translation {
        text: "http://www.sometransitagency/alerts"
        language: "en"
      }
    }
    header_text {
      translation {
        text: "Stop at Elm street is closed, temporary
stop at Oak street"
        language: "en"
      }
    }
    description_text {
      translation {
        text: "Due to construction at Elm street the 
stop is closed. The temporary stop can be found 
300 meters north at Oak street"
        language: "en"
      }
    }
  }
}

]- header information
  ]- version of speed specification. Currently "1.0"
  ]- determines whether dataset is incremental or full
  ]- the time where this dataset was generated on server
     for determining the sequence of alert feeds
]- multiple entities can be included in the feed
  ]- unique identifier for the entity
  ]- "type" of the entity
    |- multiple periods can be defined when alert is active
    |- start time in POSIX epoch format
    |- end time in POSIX epoch format

  ]- selects which GTFS entities will be affected
    ]- valid parameters: agency_id, route_id, route_type,
      stop_id, trip (see TripDescriptor)
    ]- multiple selectors (informed_entity) can be given


  ]- cause of the alert - see gtfs-realtime.proto for valid values
  ]- effect of the alert - see gtfs-realtime.proto for valid values
  ]- the given url provides additional information
    ]- multiple languages/translations supported
      page hosted outside of Google (at provider/agency, etc.)



  ]- header for the alert will be highlighted
    ]- multiple languages/translations supported





  ]- Alert description. Additional info to the header text
    ]- multiple languages/translations supported