What City Observatory did this week
IBR’s plan to sabotage the “moveable span” alternative. The proposed $7.5 billion Portland area freeway widening project is supposedly looking at a moveable span option to avoid illegally impeding water navigation. But state DOT officials are planning to sabotage the analysis of a moveable span options as part of the Interstate Bridge Project. The Coast Guard has said a replacement for the existing I-5 bridges would need a 178 foot navigation clearance. The highway departments want a 116′ clearance fixed span. The Oregon and Washington DOTs say they are going to study a “moveable span” as a “design option” but are plainly aiming to produce a costly design that just grafts a lift-span on to their current bridge design.
A moveable span would enable a lower crossing, eliminate the need for lengthy viaducts, and reduce construction costs—but ODOT is refusing to design an option that takes advantage of these features. And the DOTs have completely ignored an immersed tube tunnel option, implying that the Coast Guard directed them to study the moveable span (which it didn’t). IBR staff have signaled they have no intention of seriously considering the fixed fixed span, and are engaged in malicious compliance.
Wile E. Coyote crashes to earth: Inclusionary Zoning in Portland. Portland’s inclusionary zoning requirement is a slow-motion train-wreck; apartment permits are down by sixty percent in the City of Portland, while apartment permitting has more than doubled in the rest of the region.
Inclusionary zoning in Portland has exhibited a Wile E. Coyote pattern: apartment starts stayed high initially, until a backlog of grandfathered units got built. Since then Portland apartment permits have plummeted.
Traffic studies are junk science. There’s a whole web of pseudo-science underpinning the professions of transportation and land use planning in the United States. Donald Shoup has famously debunked the statistical fraud in studies that purport to estimate parking requirements. A new study summarized by Streetsblog makes a powerful case that a parallel requirement–transportation impact studies–are equally flawed.
It’s common in many development or permitting processes to require a traffic impact study–a statistical estimate of how many more trips (almost invariably automobile trips) will be “caused” by building a new shopping center or apartment complex or housing subdivision. Cities use these impact studies to require developers to offset the impacts attributed to their development: for example, by widening roads or paying for new traffic signals or other transportation improvements. There’s a problem and a paradox.
The problem is that the statistical work used to estimate traffic generation is based on observations of environments that are not necessarily good predictors of every other development. The amount of trip generation from a new greenfield mall in a Florida or Arizona suburb may be a poor guide to the added traffic associated with infill development in a dense urban setting.
The paradox is that the so called remedy–expanding traffic capacity–creates a kind of perverse, self-fulfilling prophecy. Cities end up taxing development to subsidize more infrastructure that encourages more travel. As study co-author Kenneth Stahl says:
“They’re being used to require traffic mitigations that only induce more driving. … You’re getting terrible policy outcomes, and they’re based on analyses that aren’t reliable at all.”
Finally, it’s worth noting that traffic impact studies seldom, if ever, consider the counterfactual: what would happen to travel, particularly in a regional context, if more development isn’t added in a particular location. Particularly in urban settings, adding more apartments or more shopping opportunities might tend to put more people closer to common destinations, shortening auto trips, facilitating more biking and walking, and actually leading to reduced driving.
Housing’s “Missing Bottom.” Over the past few years, the “missing middle” has been a popular slogan in housing debates, pointing to the paucity of smaller multi-family buildings that use to be common in America’s residential neighborhoods until the widespread adoption of exclusionary single family zoning. Writing at the blog “Building the Skyline”, Jason Barr, makes the case that we need to be thinking about a the “missing bottom”–in this case the bottom along a different dimension, housing price and age.
Barr points out that the way we get most affordable housing in the US is that people move into housing that has depreciated because it has gotten older. Careful economic studies have traced out the steady downward progression of the housing stock, which is generally most expensive (and most occupied by higher income households when it is new) and which over time, declines in price, and is occupied by successively less well-to-do households.
Research and history suggest that we need to think about housing and cities not as static entities but as dynamic systems. Newly constructed middle-income housing not only benefits those in the middle class but is also the primary means by which low-income housing gets produced.
Because the way we get housing at the “bottom” of the market depends on this process of downward filtering, when we don’t build enough new housing at the top, the old housing doesn’t filter downward in price. Barr presents a nice summary of some of the recent research on the subject (showing, for example, how as higher income people moving into new housing, a chain of moves is triggered that creates vacancies for low income households). He also has some key policy recommendations, centered on increasing housing supply.
If we want to walk more, we need to do things differently. Walking and urban advocate Jeff Speck has a seemingly innocuous-sounding column at Next City, observing the annual “Walk to Work” day. Speck argues that rather than the kind of occasional and odd effort to walk to work, which for some is a once yearly exceptional activity, we need to think about how we changes things so that walking is common the other 364 days of the year. He observes:
More than three quarters of us get to work by car. Most of us do this not because we want to, but because we have no good alternative. Seventy-five years of sprawl, highway building, and transit disinvestment have created a national landscape that makes car ownership an obligation for almost everyone. The automobile is no longer an instrument of freedom, but rather a bulky, expensive, and dangerous prosthetic device, a prerequisite to viable citizenship.
Speck has a succinct agenda: Build housing near transit, reform parking and fight highways. If there were more places to live near frequent transit, transit would work better, and fewer people would need to drive. We have too much parking, thanks to a hidden and byzantine system of regulations and subsidies that generates more driving and car dependence. And our ever expanding highway system simply generates more travel and more sprawl. Walking is great, but once a year performative measures just underscore how much we need serious change.