diff --git a/src/effectvehicle_base.h b/src/effectvehicle_base.h
--- a/src/effectvehicle_base.h
+++ b/src/effectvehicle_base.h
@@ -33,6 +33,7 @@ struct EffectVehicle : public Specialize
 
 	void UpdateDeltaXY(Direction direction);
 	bool Tick();
+	TransparencyOption GetTransparencyOption() const;
 };
 
 /**