Local Benefits vs. Regional Benefits
It is important to distinguish between regional and local benefits produced by TOD, and the magnitude of benefits at both scales of measurement. Intuition suggests that station-area development involving mixed use and higher employment and residential densities will induce more pedestrian and transit trips. Several studies lend credence to this belief. However, since the ideal TOD is still a planner’s vision, researchers have resorted to comparing older neighborhoods that approximate TOD with conventional suburban neighborhoods that do not. These studies suggest that the increase in non-auto trips, although small, is measurable (Bernick and Cervero 1996).
Yet local area benefits may not translate to regional benefits, especially when weighed against the costs of the transit investments needed to link individual TOD centers. Consequently, the central question for planners and decision makers is the magnitude of TOD’s regional impact, namely reduced congestion and improved air quality that are the principle concerns of the traveling public. Nelson and Niles (1999), after reviewing the empirical studies to date, suggest that they provide insufficient evidence that TOD on a regional scale, even when supported by large transit investments, is likely to produce significant regional benefits.
It is important, therefore, to understand the factors that determine the regional and local success of TOD. This paper reviews the key factors and suggests where further work is needed that will expand our understanding of the strength of each and hence of TOD’s potential. We focus particularly on the obstacles posed to
