And Greensboro has amended its building code to allow higher density in planned communities.

The builder is often allowed more density than might otherwise be permitted on limited land because the rest of the property is being preserved as open space.

In 2006, residents approved changes to deed restrictions to allow greater density of urban mixed-use and residential construction.

It advocates relaxing zoning rules to allow greater density and to give homeowners more freedom to alter their houses.

Zoning reforms that allow greater urban density as well as designs for walking and bicycling can greatly reduce energy consumed for transportation.

However the Honeycomb housing concept - which allows relatively high density - does appear to overcome some of the concerns here.

The land had to be rezoned to allow greater density - almost unavoidable if prices are to be held down - and then cleared and regraded.

Optical mark reading software allows greater density of information per sheet and greater reliability.

Allowing greater density where it is needed would expand property rights.

But the code allows higher density for churches and doctors' offices, and makes an exception to encourage tall towers on large plots with open space.