With the re-introduction of hybrid designs, trolleybuses are no longer tied to overhead wires. The Public Service Company of New Jersey, with Yellow Coach, developed "All Service Vehicles;" trackless trolleys capable of operating as gas-electric buses when off wire, and used them successfully between 1935 and 1948. Since the 1980s, systems such as Muni in San Francisco, TransLink in Vancouver, and Beijing, among others, have bought trolleybuses equipped with batteries to allow them to operate fairly long distances away from the wires. Supercapacitors can be also used to move buses short distances.