The electric Urban Concept is Audiâ??s radical vision of a zero-emission city car. Itâ??s fun to drive and, better still, it will be built Main text:The Frankfurt Motor Show is the worldâ??s biggest motor show. At the recent 2011 exhibition, upwards of 100 new models were unveiled: there was an awful lot to get excited about at Frankfurt. Yet this, the zero-emission, all-electric Audi Urban Concept, was, perhaps, the most intriguing exhibit of all.