diff --git a/busManager/coord/models.py b/busManager/coord/models.py
index 6490a60..15ae53e 100644
--- a/busManager/coord/models.py
+++ b/busManager/coord/models.py
@@ -230,7 +230,7 @@ class Traveller(models.Model):
         new_start_date = None
         new_end_date = None
 
-        for travellerRoute in TravellerRoute.objects.filter(traveller=self):
+        for travellerRoute in TravellerRoute.objects.filter(traveller=self.id):
             route_start = travellerRoute.travel_start_date
             route_end = travellerRoute.travel_end_date
             if route_start is not None: