Box 3-1


Land development patterns that describe the built environment, particularly in the context of those features that encourage more compact development, have come to be characterized in the literature by the shorthand of “the D’s.” The initial three D’s, first used by Cervero and Kockelman (1997), have now been expanded to five:

  • Density: Population and employment by geographic unit (e.g., per square mile, per developed acre).

  • Diversity: Mix of land uses, typically residential and commercial development, and the degree to which they are balanced in an area (e.g., jobs–housing balance).

  • Design: Neighborhood layout and street characteristics, particularly connectivity, presence of sidewalks, and other design features (e.g., shade, scenery, presence of attractive homes and stores) that enhance the pedestrian- and bicycle-friendliness of an area.

  • Destination accessibility: Ease or convenience of trip destinations from point of origin, often measured at the zonal level in terms of distance from the central business district or other major centers.

  • Distance to transit: Ease of access to transit from home or work (e.g., bus or rail stop within ¼ to ½ mile of trip origin)

such as establishing maximum rather than minimum parking requirements and introducing market-based parking fees, are also needed. As will be shown, however, few studies include many or all of these dimensions.

Even if it can be demonstrated that more compact, mixed-use development is associated with lower VMT, encourages mode shifts, and

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