MUCH OF THE DEBATE about the Association of Bay Area Governments' Plan Bay Area centered around one core principle. That's the contention that building high-density housing adjacent to transit lines will cause higher transit usage, in turn curbing global warming-causing carbon emissions.

It's a grand theory that's encouraged altruistic support for large apartment blocks clustered in transit-accessible areas. If this "new urbanism" concept truly works, Plan Bay Area makes sense.
If it's hype and not backed by statistics, then it's just greenwashing lucrative large-scale real estate development.

Other than the oft-heard "everyone knows" that high-density housing and transit usage are linked, proof is in short supply. It does work in big-city New York and some regional central cities including San Francisco. The dilemma is that there's little data confirming that the claimed housing-transit nexus makes sense in suburbia or smaller cities.

If transit-oriented development can thrive in any of the less-dense metro areas, it would be in Portland. New urbanism and transit-oriented "smart growth" guide the Oregon city's planning.

Portlanders have invested heavily in their excellent TriMet transit system.

The results are disappointing. In 1989, only 2.1 percent of Portland residents used transit. Twenty years later after creation of dense housing near bus and rail stops, that increased to only 2.8 percent.
As the pioneering Genevieve Giuliano-UC Berkeley study reported, "a large proportion of all commuting cannot be explained by job access considerations, housing preferences or other such factors."
While frustrating to planners, proximity to transit is a minor factor when making job and housing decisions.

Read more in the Marin IJ