Today bicycle-friendliness is considered a factor in the sustainability of big cities. The city's proposed new bicycle network, now undergoing final revisions, will roughly double the miles of marked bike lanes to about 400, not counting 40 or so miles of separate trails on parklands. The bike lanes will come over the next decade as streets are repaved. Notable parts of the new network are more north-south routes, including longer stretches that will make for easier riding from South Philadelphia all the way to Temple University along 13th and 15th streets.