The above figure presents two urban spatial structures in terms of form, pattern, and interaction. In the first case, the city is more transit-oriented while in the second, the car dominates.
- Spatial form. The spatial aspect of a city in terms of its extent. The first case is more centralized and compact, with corridors shaping the urban form, and the second case is grid-like with limited centrality. In the first case, the average commuting distance is likely shorter than in the second.
- Spatial interaction. The intensity of movements between spatial entities. In the first case, interactions are oriented along major axes and have a high intensity that can be efficiently serviced by public transit. In the second case, interactions have a random pattern and a low intensity.
- Spatial pattern. The organization of the land use in terms of locations. The pattern is zonal, somewhat radial, and concentrated in the first case. In the second case, the pattern is highly fragmented and dispersed. It would be difficult to achieve agglomeration economies and economies of scale in transit in such an urban environment.
The second city is likely to have far more environmental impacts attributed to land use, simply because of its spatial structure and the transportation demands such a spatial structure is associated with. Yet, the first city is likely to have a higher concentration of environmental externalities, particularly in central areas.