def write_temporal_networks_by_route_type(gtfs, extract_output_dir):
util.makedirs(extract_output_dir)<EOL>for route_type in route_types.TRANSIT_ROUTE_TYPES:<EOL><INDENT>pandas_data_frame = temporal_network(gtfs, start_time_ut=None, end_time_ut=None, route_type=route_type)<EOL>tag = route_types.ROUTE_TYPE_TO_LOWERCASE_TAG[route_type]<EOL>out_file_name = os.path.join(extract_output_dir, tag + "<STR_LIT>")<EOL>pandas_data_frame.to_csv(out_file_name, encoding='<STR_LIT:utf-8>', index=False)<EOL><DEDENT>
Write temporal networks by route type to disk.

Parameters
----------
gtfs: gtfspy.GTFS
extract_output_dir: str