Raise the main storey on slender columns so that the ground beneath flows under the building (for circulation, cars, gardens or public space) and the rooms are lifted into light, air and view.
People above, traffic below
In a dense centre, give the ground to vehicles and service, and build a continuous pedestrian level above it (a podium and highwalks joining the buildings) so that people never meet the traffic.
Buchanan’s report proposed environmental areas free of through traffic and, for the most intensive centres, a complete separation of levels. The City of London adopted a plan for a network of elevated walkways; the Barbican estate (Chamberlin, Powell and Bon, 1955–82) was built on a podium over car parks and service roads, its terraces and towers linked by highwalks above the streets.
Related rules
House a whole community in one tall slab: stack duplex flats that run through the block with light on both sides, put shops and services on an interior street half-way up, and give the roof to everyone.
Where density is needed, build tall blocks widely spaced, so that every dwelling has sun, air and a view, and the ground freed between them becomes green space.
Give high housing a deck every few floors, wide enough to be a street, on which front doors open and neighbours meet, and join the decks from block to block into a continuous network across the city.
Run the decks the whole length of a continuous, snaking slab and use the fall of the site so that every deck arrives at ground level somewhere: the roofline stays level while the number of storeys rises as the ground drops.
Park Hill: decks 10 ft (3 m) wide every third floor; 4 to 13 storeys under one level roof
Cite this page Chris Paton, “People above, traffic below”, The Textbook of Architecture, https://textbookofarchitecture.com/rule/vertical-segregation. Text, drawings and models licensed under CC BY-NC 4.0.