the late 1960s. Between 2000 and 2006, ridership growth was at 40% in London, while ridership in the rest of the country fell by 6%. The bus fleet grew to cope with demand, from around 5,500 buses to over 8,000. Traffic speeds across London improved, and levels of air pollution in central London decreased. Vehicles , the London Buses fleet total of 8,795 buses includes 3,854 hybrid buses, 785 battery electric buses, and 22 hydrogen fuel cell buses. The zero emission fleet is the second largest in Europe, behind Moscow. All buses have been low-floor and accessible since 2006, one of the first major cities in the world to achieve this. The various bus operators operate a wide variety of vehicles, about the only immediately obvious common feature being their use of a largely red livery (mandatory since 1997). For each bus route, London Buses sets a specification for buses to be used, with the choice of particular vehicle that meets the specification left up to the operator. Particular examples of London Buses specification include the use of separate exit doors (increasingly unusual on buses in the United Kingdom outside London) and, on double-deckers, the use of a straight staircase. Additionally, London Buses has previously specified that vehicles operating in London use traditional printed roller destination blinds, whereas in most other parts of the country, electronic dot matrix or LED displays are the norm on new buses. History From the early days of motor bus operation by the London General Omnibus Company (LGOC) in the 1900s (decade) until the 1960s, London went its own way, designing its own vehicles specially for London use rather than using the bus manufacturers' standard products used elsewhere. The Associated Equipment Company (AEC) was created as a subsidiary of the LGOC in 1912 to build buses and other equipment for its parent company, and continued in the ownership of LGOC and its successors until 1962. Many of London's local service buses over this period were built by AEC, although other manufacturers also built buses to London designs, or modified their own designs for use in London. The last bus specifically designed for London was the AEC Routemaster, built between 1956 and 1968. Since then, buses built for London's local services have all been variants of models built for general use elsewhere, although bus manufacturers would routinely offer a 'London specification' to meet specific London requirements.