What concept did Geoffrey Jellicoe propose for urban planning where cars are relocated to upper levels or streets below?

Geoffrey Jellicoe proposed the concept of "Motopia," which envisions a restructured urban environment where vehicles are relocated to elevated levels or placed in subterranean streets. This approach reflects a vision for the future of urban design that prioritizes pedestrians and green spaces, reducing the dominance of cars on the surface level. By moving automotive traffic out of sight, Motopia aims to create more accessible, safer, and environmentally friendly urban spaces. Jellicoe believed that this kind of urban reorganization would not only improve aesthetics but also enhance the quality of life for residents.

Other concepts like Metapolis, which discusses cities expanded without traditional forms, arcology, emphasizing dense ecological architecture, and Marine City, which envisions floating urban environments, do not specifically relate to the relocation of cars as outlined in Jellicoe's Motopia. Each represents a different perspective on urban planning, but Motopia uniquely focuses on the integration and management of vehicles within the urban fabric.