diff --git a/src/road.cpp b/src/road.cpp
index 788c611654..d143ae652d 100644
--- a/src/road.cpp
+++ b/src/road.cpp
@@ -141,7 +141,7 @@ bool HasAnyRoadTypesAvail(CompanyID company, RoadTramType rtt)
  */
 bool ValParamRoadType(RoadType roadtype)
 {
-	return roadtype != INVALID_ROADTYPE && HasRoadTypeAvail(_current_company, roadtype);
+	return roadtype < ROADTYPE_END && HasRoadTypeAvail(_current_company, roadtype);
 }
 
 /**