The classifieds in this issue include two chief executive officer positions!
 

A report released Sept. 1 by the Transportation Research Board (TRB), Driving and the Built Environment: The Effects of Compact Development on Motorized Travel, Energy Use, and CO2 Emissions, shows that—assuming that compact development focuses on new and replacement housing, as converting existing housing to higher densities could be prohibitively difficult—significant increases in density would result in modest short-term reductions in personal travel, energy use, and CO2 emissions, but the reductions would grow over time. It points to the importance of “compact, mixed-use development—individuals living in denser environments with jobs and shopping close by” —that allow for shorter trip lengths and more options for public transit, walking, and biking as viable alternatives to driving.

The authors cite research studies estimating that doubling residential density in a metropolitan area might lower household driving between 5 percent and 12 percent. If higher density were paired with more concentrated employment and commercial locations, and combined with improvements to public transit and other strategies to reduce automobile travel, household driving could be lowered by as much as 25 percent. Reducing vehicle use would also mean less petroleum use and reduced carbon dioxide emissions.

The report recommended additional research in five areas:
* Isolating the effects of different types of development patterns on travel behavior;
* Changes in metropolitan areas at finer levels of spatial detail to help inform the needs and opportunities for policy intervention;
* What works and what does not with policy interventions to promote more compact, mixed-used development;
* Threshold population and employment densities to support rail and bus transit and walking and bicycling; and
* Changing housing preferences and travel patterns of an aging population, new immigrant groups, and young adults to help determine whether future trends will differ from those of the past.

Copies of the report are available from TRB at its web site.

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