--- a/src/vehicle.cpp	Wed Jun 13 19:34:33 2007 +0000
+++ b/src/vehicle.cpp	Wed Jun 13 23:14:08 2007 +0000
@@ -43,7 +43,7 @@
 #include "group.h"
 #include "economy.h"
 
-#define INVALID_COORD (-0x8000)
+#define INVALID_COORD (0x7fffffff)
 #define GEN_HASH(x, y) ((GB((y), 6, 6) << 6) + GB((x), 7, 6))