diff --git a/gtfs-realtime/proto/gtfs-realtime.proto b/gtfs-realtime/proto/gtfs-realtime.proto
index e050fc19..63900085 100644
--- a/gtfs-realtime/proto/gtfs-realtime.proto
+++ b/gtfs-realtime/proto/gtfs-realtime.proto
@@ -644,6 +644,7 @@ message Alert {
     CONSTRUCTION = 10;
     POLICE_ACTIVITY = 11;
     MEDICAL_EMERGENCY = 12;
+    SPECIAL_EVENT = 13;     // A special one-time or recurring event such as a parade, festival, performance, farmers market, or sporting event.
   }
   optional Cause cause = 6 [default = UNKNOWN_CAUSE];
 
@@ -1256,4 +1257,4 @@ message ReplacementStop {
 
   // The following extension IDs are reserved for private use by any organization.
   extensions 9000 to 9999;
-}
\ No newline at end of file
+}
diff --git a/gtfs-realtime/spec/en/reference.md b/gtfs-realtime/spec/en/reference.md
index 1c4b96dc..ec060f6d 100644
--- a/gtfs-realtime/spec/en/reference.md
+++ b/gtfs-realtime/spec/en/reference.md
@@ -398,6 +398,7 @@ Cause of this alert.
 | **CONSTRUCTION** |
 | **POLICE_ACTIVITY** |
 | **MEDICAL_EMERGENCY** |
+| **SPECIAL_EVENT** |
 
 ## _enum_ Effect
 
diff --git a/gtfs-realtime/spec/en/service-alerts.md b/gtfs-realtime/spec/en/service-alerts.md
index 261afd97..519620c8 100644
--- a/gtfs-realtime/spec/en/service-alerts.md
+++ b/gtfs-realtime/spec/en/service-alerts.md
@@ -44,6 +44,7 @@ What is the cause of this alert? You may specify one of the following:
 *   Construction
 *   Police activity
 *   Medical emergency
+*   Special Event
 
 ## Effect