diff --git a/src/rides/index.ts b/src/rides/index.ts
index edd5589..63291ba 100644
--- a/src/rides/index.ts
+++ b/src/rides/index.ts
@@ -2,7 +2,7 @@ import { Ride } from "../types/ride"
 import { Scheduler } from "./scheduler"
 import { deleteRide } from "../data/redis"
 import { logNames, logger } from "../logs"
-import { RideNotInTimeError } from "../utils/errors"
+import { RideNotInTimeError, rideFailureReason } from "../utils/errors"
 
 const schedulers: Record<string, Scheduler> = {}
 
@@ -26,11 +26,16 @@ export const startRideNotifications = async (ride: Ride, isExisting: boolean = f
     rideLogger.info(registerRideLog.success, { ...ride })
     return { success: true, rideId: ride.rideId }
   } catch (error) {
-    if (!(error instanceof RideNotInTimeError)) {
-      rideLogger.error(registerRideLog.failed, { error, ...ride })
+    const reason = rideFailureReason(error)
+
+    // Warn, not error: the ride is outside the startable window, which isn't a server fault — but still log it.
+    if (error instanceof RideNotInTimeError) {
+      rideLogger.warn(registerRideLog.failed, { reason, ...ride })
+    } else {
+      rideLogger.error(registerRideLog.failed, { error, reason, ...ride })
     }
 
-    return { success: false }
+    return { success: false, reason }
   }
 }
 
diff --git a/src/rides/scheduler.ts b/src/rides/scheduler.ts
index d8fc4bc..65fac05 100644
--- a/src/rides/scheduler.ts
+++ b/src/rides/scheduler.ts
@@ -56,7 +56,7 @@ export class Scheduler {
         await deleteRide(ride.rideId)
       }
 
-      throw new RideNotInTimeError(logNames.scheduler.rideInPast)
+      throw new RideNotInTimeError(logNames.scheduler.rideInPast, "ride_in_past")
     }
 
     if (env === "production" && dayjs(route.departureTime).add(route.delay, "minutes").diff(dayjs(), "minutes") > 60) {
@@ -70,7 +70,7 @@ export class Scheduler {
         await deleteRide(ride.rideId)
       }
 
-      throw new RideNotInTimeError(logNames.scheduler.rideInFuture)
+      throw new RideNotInTimeError(logNames.scheduler.rideInFuture, "ride_in_future")
     }
 
     if (!isExisting) {
diff --git a/src/utils/errors.ts b/src/utils/errors.ts
index 7da910f..4859ca2 100644
--- a/src/utils/errors.ts
+++ b/src/utils/errors.ts
@@ -1,2 +1,26 @@
-export class RideNotInTimeError extends Error {}
-export class NotFoundRouteForRide extends Error {}
+// Returned to the client alongside `success: false`, so it can tag its report with the cause.
+export type RideFailureReason = "route_not_found" | "ride_in_past" | "ride_in_future" | "internal_error"
+
+export class RideNotInTimeError extends Error {
+  constructor(
+    message: string,
+    readonly reason: Extract<RideFailureReason, "ride_in_past" | "ride_in_future">,
+  ) {
+    super(message)
+    this.name = "RideNotInTimeError"
+  }
+}
+
+export class NotFoundRouteForRide extends Error {
+  readonly reason: RideFailureReason = "route_not_found"
+
+  constructor(message: string) {
+    super(message)
+    this.name = "NotFoundRouteForRide"
+  }
+}
+
+export const rideFailureReason = (error: unknown): RideFailureReason => {
+  if (error instanceof RideNotInTimeError || error instanceof NotFoundRouteForRide) return error.reason
+  return "internal_error"
+}