diff --git a/src/services/NotificationService.ts b/src/services/NotificationService.ts
index 3613803..76651bd 100644
--- a/src/services/NotificationService.ts
+++ b/src/services/NotificationService.ts
@@ -19,7 +19,9 @@ export class NotificationService {
     return this._lastRefreshedTimeMs;
   }
 
-  constructor(private repository: GetterRepository) {}
+  constructor(private repository: GetterRepository) {
+    this.etaSubscriberCallback = this.etaSubscriberCallback.bind(this);
+  }
 
   /**
    * An object of device ID arrays to deliver notifications to.
@@ -79,13 +81,19 @@ export class NotificationService {
       return;
     }
 
-    await Promise.all(this.deviceIdsToDeliverTo[tuple.toString()].map(async (deviceId) => {
-      await this.sendEtaNotificationImmediately({
+    const indicesToRemove = new Set();
+    await Promise.all(this.deviceIdsToDeliverTo[tuple.toString()].map(async (deviceId, index) => {
+      const deliveredSuccessfully = await this.sendEtaNotificationImmediately({
         deviceId,
         shuttleId: eta.shuttleId,
         stopId: eta.stopId,
       });
+      if (deliveredSuccessfully) {
+        indicesToRemove.add(index);
+      }
     }));
+
+    this.deviceIdsToDeliverTo[tuple.toString()] = this.deviceIdsToDeliverTo[tuple.toString()].filter((_, index) => !indicesToRemove.has(index));
   }
 
   /**
@@ -102,7 +110,6 @@ export class NotificationService {
       this.deviceIdsToDeliverTo[tuple.toString()].push(deviceId);
     }
 
-    // Refresh the subscriber with the updated array if needed
     this.repository.unsubscribeFromEtaUpdates(this.etaSubscriberCallback);
     this.repository.subscribeToEtaUpdates(this.etaSubscriberCallback);