diff --git a/road_cmd.c b/road_cmd.c
--- a/road_cmd.c
+++ b/road_cmd.c
@@ -293,7 +293,7 @@ int32 CmdBuildRoad(TileIndex tile, uint3
 
 	/* Road pieces are max 4 bitset values (NE, NW, SE, SW) and town can only be non-zero
 	 * if a non-player is building the road */
-	if ((p1 >> 4) || (_current_player < MAX_PLAYERS && p2 != 0) || !IsTownIndex(p2)) return CMD_ERROR;
+	if ((p1 >> 4) || (_current_player < MAX_PLAYERS && p2 != 0) || !IsValidTownID(p2)) return CMD_ERROR;
 	pieces = p1;
 
 	tileh = GetTileSlope(tile, NULL);