diff --git a/src/autoslope.h b/src/autoslope.h
new file mode 100644
--- /dev/null
+++ b/src/autoslope.h
@@ -0,0 +1,42 @@
+/* $Id$ */
+
+/** @file autoslope.h */
+
+#ifndef AUTOSLOPE_H
+#define AUTOSLOPE_H
+
+#include "depot.h"
+
+/**
+ * Autoslope check for tiles with an entrance on an edge.
+ * E.g. depots and non-drive-through-road-stops.
+ *
+ * The test succeeds if the slope is not steep and at least one corner of the entrance edge is on the TileMaxZ() level.
+ *
+ * @note The test does not check if autoslope is enabled at all.
+ *
+ * @param tile The tile.
+ * @param z_new New TileZ.
+ * @param tileh_new New TileSlope.
+ * @param entrance Entrance edge.
+ * @return true iff terraforming is allowed.
+ */
+static inline bool AutoslopeCheckForEntranceEdge(TileIndex tile, uint z_new, Slope tileh_new, DiagDirection entrance)
+{
+	if (IsSteepSlope(tileh_new) || (GetTileMaxZ(tile) != z_new + GetSlopeMaxZ(tileh_new))) return false;
+	return ((tileh_new == SLOPE_FLAT) || CanBuildDepotByTileh(entrance, tileh_new));
+}
+
+/**
+ * Tests if autoslope is enabled for _current_player.
+ *
+ * Autoslope is disabled for town/industry construction and old ai players.
+ *
+ * @return true iff autoslope is enabled.
+ */
+static inline bool AutoslopeEnabled()
+{
+	return (_patches.autoslope && IsValidPlayer(_current_player) && !_is_old_ai_player);
+}
+
+#endif /* AUTOSLOPE_H */