The notion that we need more public transit starts with a premise that most of us can embrace. We, meaning human beings — and particularly those in developed countries — are messing up the atmosphere.

How? Well, in lots of ways, but according to the U.S. Environment Protection Agency, the cars and trucks we drive are responsible for anywhere between 50 and 90 percent of the air pollution in urban areas. And, even if you think that automobile transportation is an American birthright guaranteed by God, you’re no doubt aware of the unhealthy effects of the hydrocarbons and other junk that we’re taking in — and you probably can get behind the idea that maybe pollution would decrease if we drove less.

Mass transit, however, needs a critical mass of customers to make sense. You wouldn’t build a subway system across the Gobi desert because only the odd nomad would be around to use it. Similarly, many U.S. cities, including ours, while hardly deserts, have spread themselves so wide and so thin that for years, city planners figured that roads and freeways were the only cost-efficient form of transportation.  

Ultimately, however, as the increasing number of cars boosted pollution, congestion and commuting times, planners came up with a kind of retrofit: transit would become cost effective if you encouraged high-density development around it. The strategy, called, TOD or transit-oriented development, when translated from plannerese,  means building up housing, offices and retail outlets within a half-mile or so of a rail stop, thus creating a walkable neighborhood with lots of pedestrian amenities. All that would encourage people to walk, bicycle and use transit instead of driving. Air would get cleaner, dependence on foreign oil would drop, and a thousand flowers would bloom.

No fewer than a jillion U.S. communities either have or are trying to ramp up TOD around the transit they already have or, in the case of the Twin Cities, are building (and hope to build as soon as we can scratch up the billions of dollars we need).

But here’s the crucial question: Does TOD really decrease driving?

Studies have come down on both sides of the issue. The latest, from Daniel G. Chatman, assistant professor of urban and regional planning at the University of California, Berkeley, made a pretty thorough investigation of the matter and concluded that people living in TOD areas did drive less, but — and here’s the surprise — not because of the availability of transit.

Households surveyed

Makes no sense, you say? Well, read on. Chatman surveyed a couple of thousand households living — some in new TOD developments and some in older housing — within two miles of 10 rail stations in the New Jersey suburbs of New York City, including Trenton, South Amboy, Westfield and South Orange (which have population densities similar to Minneapolis, 3,000 to 8,000 people a square mile). He asked them about the type of housing they lived in, their access to parking, their work and non-work travel patterns, their demographics and reasons for choosing their neighborhoods. He added parking data collected from a field survey and then figured how each of the factors correlated with auto use.

What he concluded from all this was that it wasn’t so much the availability of transit that made people use cars less, but density itself. Higher density means “lower on- and off-street parking availability, better bus service and more jobs, stores and people within walking distance.”

People who lived in the newer housing, usually made up of small rental units, tended to use cars less than everybody else, possibly, he suggests, because they are younger and have lower incomes. Most crucial seems to be lousy parking, and as a survivor of alternate-side-of-the-street parking regulations in New York City, I can attest that nothing encourages use of mass transit more than such auto-related misery.

Instead of making multi-billion dollar investments in rail transit, Chatman argues, we may be able to reduce energy use and pollution just as much by creating incentives for higher-density mixed-use developments (incorporating housing, retail and offices) in certain areas while strictly limiting parking. Problem is, the local inconveniences of greater congestion and less parking would probably tick off neighbors and their elected representatives. Working all that out, he says,”is the planning puzzle that deserves our focused attention. The pursuit of rail-oriented development may be a distraction.”

As I was wading through Chatman’s multi-variate regression analyses (OK, I mostly skimmed them), I happened to recall that I’d recently read another study — this one local — that teases out information complementing his findings.

The purpose of this one was to find out how much transit matters to employers and developers when they decide where to locate a project or business. To that end, Yingling Fan, an assistant professor of public affairs at the University of Minnesota’s Humphrey School of Public Affairs, and Andrew Guthrie, a research fellow, conducted a series of open-ended interviews with 24 developers, 16 corporados and three commercial real-estate brokers.

The answer researchers got: transit — not so much.  

Employers, for example, liked the idea of being near a rail or bus line — in theory, at least. They are aware that members of the younger millennial generation (born after 1982) prefer urban living and transit access. Attracting them would be easier for businesses locating near transit. But employers also want to retain current workers, many of whom already commute by car. If they moved their business to a denser area where parking was less available, those older employees might ditch them for the competition. 

About a third of the 24 developers interviewed said they considered mass transit an important factor in location. But if the site proved more expensive than otherwise, or if there would be more red tape involved than with another location, they weren’t interested. And apparently red tape abounds. Developers complained in particular of zoning codes that allowed only a single-use, high-minimum parking requirements and low-maximum densities.

List of recommendations

Yingling and Guthrie issued a long list of recommendations that might help nudge developers and employers toward TOD areas, including tax abatements. Local governments have already ramped up efforts — a bit — to create high-density nodes. A couple of years ago, Minneapolis hired a director of transit-oriented development, and St. Paul is now looking for one — though it’s also looking for foundation grants to fund the position. The Met Council awards grants to transit-oriented projects to clean up polluted land and aid in assembling land, but the total available is only $8 million.

Minneapolis has already changed zoning around the Blue LRT line (that’s the one running down Hiawatha) to allow higher-density housing, as many as 100 units per acre, without special permission and mixed-use buildings. Among other things, the new regulation requires less off-street parking than in other parts of the city, more pedestrian-oriented design (windows on the street, for example) and prohibits stand-alone fast-food joints. Since 2001, 1,466 units of housing have been added to the immediate area, with another 1,000 or so in the talking-about-it stage. 

Note: The last paragraph of this version reflects newer information on zoning.