diff --git a/www/js/map.js b/www/js/map.js
index a5d24c008a808963f08d0ae5f1af1eeba75aeb9c..2bcf2c3b3197a62005cf91e63e547153133cc970 100644
--- a/www/js/map.js
+++ b/www/js/map.js
@@ -313,7 +313,7 @@
 								if (value.vehicle.oos || (value.vehicle.routeID != 24 && value.vehicle.routeID != 25)) {
 									if (markers['buses'][value.vehicle.id]) {
 										markers['buses'][value.vehicle.id].setMap(null);
-										markers['buses'][value.vehicle.id] = null;
+										delete markers['buses'][value.vehicle.id];
 									}
 
 									return;