diff --git a/src/bridge_map.h b/src/bridge_map.h
--- a/src/bridge_map.h
+++ b/src/bridge_map.h
@@ -89,13 +89,13 @@ TileIndex GetNorthernBridgeEnd(TileIndex
 TileIndex GetSouthernBridgeEnd(TileIndex t);
 TileIndex GetOtherBridgeEnd(TileIndex t);
 
-uint GetBridgeHeight(TileIndex tile);
+int GetBridgeHeight(TileIndex tile);
 /**
  * Get the height ('z') of a bridge in pixels.
  * @param tile the bridge ramp tile to get the bridge height from
  * @return the height of the bridge in pixels
  */
-static inline uint GetBridgePixelHeight(TileIndex tile)
+static inline int GetBridgePixelHeight(TileIndex tile)
 {
 	return GetBridgeHeight(tile) * TILE_HEIGHT;
 }