(svn r15860) -Add: AIRoad::GetRoadVehicleTypeForCargo() to tell whether a certain cargo needs a bus- or a truckstop.

src/ai/api/ai_road.hpp

@@ -56,6 +56,14 @@ public:
 		ROADVEHTYPE_TRUCK, //!< Build objects useable for trucks and cargo trams
 	};
 
+	/**
+	 * Determines whether a busstop or a truckstop is needed to transport a certain cargo.
+	 * @param cargo_type The cargo to test.
+	 * @pre AICargo::IsValidCargo(cargo_type).
+	 * @return The road vehicle type needed to transport the cargo.
+	 */
+	static RoadVehicleType GetRoadVehicleTypeForCargo(CargoID cargo_type);
+
 	/**
 	 * Checks whether the given tile is actually a tile with road that can be
 	 *  used to traverse a tile. This excludes road depots and 'normal' road