What City Observatory did this week

1. Our old planning rules of thumb are “all thumbs.” Joe Cortright argues that many of the heuristics that have guided urban planning for decades, such as “wider streets are safer streets,” and “faster traffic flow is always better,” have long outlived their usefulness. We offer five of these outdated rules of thumb, and four new ones in their places, including “closer is better” and “slower is safer.”

2. How cutting back on driving helps the economy. While earlier predictions saw oil consumption climbing throughout the early 21st century, it turns out that oil use has flatlines, even as population continues to climb. What’s going on? Joe Cortright shows that less driving, more than any other factor, is leading to the difference. In addition to having positive benefits for the environment and urban safety, it’s also helping to balance out our macro-economy.

3. The difficulty of applying inequality measurements to cities. The Brookings Institution is perhaps the most high-profile of several outlets to try to discuss income inequality at the local level. But is that the right way of looking at it? Joe Cortright points out that measuring income inequality at the city or even metropolitan level rewards cities that have managed to push out the poor through a lack of services or high housing prices. On the flip side, if a city like Detroit adds some well-needed middle- and upper-income residents to help support its tax base, its inequality will appear to worsen.

The week’s must reads

1. One step back, one step forward: The Urbanist reports that Seattle’s Mayor Ed Murray has walked back some of the more aggressive proposals for zoning reform produced by his own affordable housing task force, including allowing duplexes in single-family zones. The other sixty-plus recommendations may still go forward. Meanwhile, Chicago is moving forward with its own proposal to eliminate parking requirements up to half a mile from rapid transit stations, and give extra density bonuses for affordable housing. The Metropolitan Planning Council has put together an interactive display to show the proposed ordinance’s effects.

2. Lawrence Schall, the president of Oglethorpe College in Atlanta, spent some time as an Uber drive to understand the new “sharing economy.” One of his major discoveries: most of his fares weren’t young professionals taking a ride back from a bar – they were often lower-income people taking routine trips that in another city might have been served by transit. Many of his riders, in fact, were going to or from MARTA stations – spending an extra $5 on his fare in addition to the $2.50 transit cost. Several even used Uber to commute. Schall’s experience hits home how stranded many Atlantans are without transit – and that Uber, though it can fill some gaps, isn’t as affordable or reliable for routine trips as a good public transit system.

3. Announced plans for a vastly improved LaGuardia Airport in New York City have met with major pushback from transit advocates, reports CityLab. In particular, groups like the Riders Alliance object that the new plans prioritize access to the airport by car, rather than transit — and that characterizations of LaGuardia as “third world” are inappropriate given the much more dire conditions in much of the New York subway and bus service.

New knowledge

1. New research on how cities dispose of vacant properties reveals a clear tradeoff: while auctions allow municipalities to make some financial gain quickly, often within 24 hours of sale, there are downsides. Because of the more difficult conditions for buyers — a lack of time to inspect the properties, for example — the land often ends up in the hands of flippers who aren’t interested in making investments. Managed sales, on the other hand, allow both planning staff and buyers more time to understand the deal, encouraging new owners who are interested in long-term investments. The study, by Margaret Dewar of the University of Michigan, found that properties sold via managed sale were in much better condition afterwards than properties sold via auction.

2. A study from UC-Berkeley’s Transportation Sustainability Research Center shows that about 40% of ZipCar customers either sell their car or don’t make a car purchase they would have otherwise. That suggests that carsharing services like ZipCar or Enterprise CarShare could have dramatic effects on overall car ownership patterns in neighborhoods where they’re heavily used, reducing parking needs and encouraging other kinds of transportation. The same study finds that 41% of ZipCar customers take transit more than they did before and 22% bike more.

3. Comparing cities in five countries, a paper from the OECD looks at what characteristics might help drive urban productivity. Among those: larger populations, as well as larger populations of nearby cities. On the flip side, cities with more governmentally fragmented metropolitan areas — that is, more sub-regional units of government — are generally less productive.

Note: Last week, we wrote that a study found that “project-based affordable housing does not improve ‘neighborhood quality’ for residents, compared to voucher-based housing subsidies.” That was a misleading description — both Housing Choice Vouchers and LIHTC projects performed better at locating recipients in high-quality neighborhoods than traditional public housing, but neither HCV nor LIHTC consistently outperformed the other.