Compact street networks support better health

Researchers reported that cities with a more compact and walkable street networks offer significant health benefits. The study by Norman Garrick of the University of Connecticut, Wesley Marshall of the University of Colorado, and Daniel Piatkowski of Savannah State University was published in the Journal of Transport & Health.

The authors wrote, "the fully gridded network – designed with its typical level of compactness, connectivity, and number of the lanes on the major roads—would expect a 15% reduction in obesity rates, a 10% reduction in high blood pressure rates, and a 6% reduction in heart disease rates, as compared to the standard fully tree-like network with its associated design characteristics."

The researchers studied 24 medium-sized California cities, from 30,000 to 150,000 in population. Some of the cities were mostly built prior to 1950, with dense street networks, and others mostly built after 1950, with sprawling, disjointed networks. In January, 2009, Better Cities & Towns (then New Urban News), first reported previous findings in these same cities: Those built mostly after 1950 suffered a rate of traffic fatalities more than three times higher than the older cities. (About 10.1 per year per 100,000 population versus 3.1 per year per 100,000 population in the years 1997 through 2005.) 

In the latest study, published in August, the authors "control for the food environment, land uses, commuting time, socioeconomic status, and street design. The results suggest that more compact and connected street networks with fewer lanes on the major roads are correlated with" the health benefits. "Given the cross-sectional nature of our study, proving causation is not feasible but should be examined in future research. Nevertheless, the outcome is a novel assessment of streets networks and public health that has not yet been seen but will be of benefit to planners and policy-makers."