diff --git a/src/roadstop.cpp b/src/roadstop.cpp
index 4f3ece2e41..cd9a3b1152 100644
--- a/src/roadstop.cpp
+++ b/src/roadstop.cpp
@@ -268,8 +268,8 @@ bool RoadStop::Enter(RoadVehicle *rv)
  */
 void RoadStop::Entry::Leave(const RoadVehicle *rv)
 {
+	assert(this->occupied >= rv->gcache.cached_total_length);
 	this->occupied -= rv->gcache.cached_total_length;
-	assert(this->occupied >= 0);
 }
 
 /**