The Formation of Urban Spatial Structures

"How do markets and design contribute to the development of cities?  Are markets or is design more likely to shape a city in such a way that an equilibrium is achieved between land consumption and commuting speed?  Should planners substitute their own designs for market forces in order to obtain a better spatial outcome or, to the contrary, should planners rely more on markets to guide urban developments? If the efficiency of urban spatial structures rests on a trade-off between land consumption and commuting speed and cost, what indicators should planners develop to monitor progress in urban structure efficiency?"