Around the Block: Urban Models with a Street Grid

Models of urban residential structure usually assume that transportation costs are a function of straight-line distance from the central business district (CBD), which is equivalent to assuming an infinite number of radial streets. This paper presents and expands existing work on urban models with an alternative transportation system, namely a dense network of vertical and horizontal streets, that is, a street grid. Several models are examined, including some with a finite number of radial commuting arteries and one with a discrete suburban worksite. Switching to a Street grid alters only one parameter in the equations of a standard urban model, but alters urban population and leads to strikingly different spatial patterns. This last result implies that the appropriate explanatory variable for estimating density functions and rent gradients is not distance from the CBD but is instead total transportation cost.