automobile automobiles avenue avenues B-class Berlin car cars cell class commute commuters complete completely conscious conservation conveyance day daylight daytime drive drives driving during eco eco-friendly ecofriendly electric emission engineering entire entirely environment environmental environmentalism environmentally Europe European exterior exteriors Federal FRG friendly fuel German Germany green Hydrogen local Mercedes metro modern motor motorcar motors of one outdoor passenger passengers photo photos preservation protecting protection public railway rapid Republic road roads separate separately shot shots single singly street streets technic technical technology the traffic tram trams transit transport transportation vehicle vehicles whole wholly zero zero-emission