Tag Archives: urban form

optimal city block length

This article in Harvard Gazette is about the optimal block length for walkability. The basic conclusion is that small is generally better, but there is some minimum below which pedestrians are spending too much time crossing streets. If I were laying out a city though, I would want to err on the side of smaller because it is much easier to close streets to vehicle traffic than to create new streets where there previously weren’t any.

10-Minute Neighborhood Analysis

This article from Kirkland, Washington describes in detail an interesting scoring scheme they applied to all of their neighborhoods. They have a good run-down on why walkable neighborhoods are good.

The ability to retain, create, and enhance 10 minute neighborhoods has benefits for users of the neighborhood and benefits for the community as a whole.

  • Health. Residents who walk or bike regularly are healthier and therefore walkable communities make it easier to live healthy lifestyles.  According to the Centers for Disease Control and Prevention, people living in walkable neighborhoods get about 35 to 45 more minutes of moderate-intensity physical activity per week and are substantially less likely to be overweight or obese than people of similar socioeconomic status living in neighborhoods that are not walkable

  • Traffic. Residents with convenient access to local goods and services are less likely to drive.  If they do drive, they have a shorter travel distance.  The 10 minute neighborhood acknowledges the value to Kirkland’s transportation system of every trip not taken and every mile not driven.

  • Transit.  Better access to transit equates to more transit users.  Regional data show that people who live within a half mile of a transit node commute less often by single-occupant vehicle (SOV) with a higher percentage using transit, carpooling, and walking or bicycling to work .

  • Demographics.  21 percent of the population aged 65 and older does not drive – and that segment of the population is projected to grow significantly .  Older non drivers need options so they remain engaged with their communities.

  • Clean Air.  Less traffic means cleaner air and less greenhouse gas emissions.

  • Social Connectivity.  Pedestrian activity and local gathering places help build social cohesion and eyes on the street help people feel safer in their communities.

  • Market Forces.  Recent surveys indicate that a majority of Americans want to live in walkable neighborhoods served by good transit .  Those numbers are significantly stronger for younger Americans and those who plan to move in the future, a strong representation of the future real estate market.

  • Stronger Retail.  A local customer base is good for local businesses.

social interaction in cities

Here’s an interesting article from the University of Bern, Switzerland, on social interaction in cities. The engineer in me likes to see some hard data and theory applied in the social sciences.

Cities and the Structure of Social Interactions: Evidence from Mobile Phone Data

Social interactions are considered pivotal to urban agglomeration forces. This study employs a unique dataset on mobile phone calls to examine how social interactions differ across cities and peripheral areas. We first show that geographical distance is highly detrimental to interpersonal exchange. We then reveal that individuals residing in high-density locations do not benefit from larger social networks, but from a more efficient structure in terms of higher matching quality and lower clustering. These results are derived from two complementary approaches: Based on a link formation model, we examine how geographical distance, network overlap, and sociodemographic (dis)similarities impact the likelihood that two agents interact. We further decompose the effects from individual, location, and time specific determinants on micro-level network measures by exploiting information on mobile phone users who change their place of residence.

And here’s a more touchy-feely article in Vox on how the U.S. suburban development pattern discourages social interaction.

the key ingredient for the formation of friendships is repeated spontaneous contact. That’s why we make friends in school — because we are forced into regular contact with the same people. It is the natural soil out of which friendship grows…

This kind of spontaneous social mixing doesn’t disappear in post-collegiate life. We bond with co-workers, especially in those scrappy early jobs, and the people who share our rented homes and apartments.

But when we marry and start a family, we are pushed, by custom, policy, and expectation, to move into our own houses. And when we have kids, we find ourselves tied to those houses. Many if not most neighborhoods these days are not safe for unsupervised kid frolicking. In lower-income areas there are no sidewalks; in higher-income areas there are wide streets abutted by large garages. In both cases, the neighborhoods are made for cars, not kids. So kids stay inside playing Xbox, and families don’t leave except to drive somewhere.

I buy this about 75%. I am lucky to live and work in a highly walkable urban neighborhood, and I do have a lot of friendly spontaneous interactions with people around the neighborhood. I have a “scrappy” job where I bond with my co-workers, like soldiers in the trenches. I am also a middle-aged family person and somewhat of an introvert. Part of the reason I don’t have a lot of close adult friendships outside of work and family is that between work and family, I have all the human interaction I can really handle. If I have 15 minutes free on a given day, I would rather spend it alone than interacting with yet another person. I suppose this could change when the kids get a little older and/or when I don’t have to work so much, assuming I live long enough for these things to happen. So I’m just saying there are family pressures, financial and career pressures, and personality differences that influence these things alongside urban form.

Back to the first article, it suggests that high school, college, band camp, and even most workplaces might not be the best model of the most fulfilling and productive social interactions that can develop among adults in the best cities. In high school and college we tend to form small, tight-knit groups where most people in the group network only within the group. The first article above, if I am interpreting it correctly, describes a case where not only are individuals interacting frequently within a social network, but relatively open social networks themselves are interacting with each other as individuals within them interact in random and freewheeling ways. It’s wonderful. Now if you’ll excuse me I’m going to sit on my couch for a little while, watch some TV, unwind and recharge so I can handle the social interaction that will be thrown at me tomorrow.

September 2016 in Review

3 most frightening stories

  • The U.S. and Russia may have blundered into a proxy war in Syria. And on a loosely related war-and-peace note, Curtis LeMay was a crazy bastard.
  • The ecological footprint situation is not looking too promising: “from 1993 to 2009…while the human population has increased by 23% and the world economy has grown 153%, the human footprint has increased by just 9%. Still, 75% the planet’s land surface is experiencing measurable human pressures. Moreover, pressures are perversely intense, widespread and rapidly intensifying in places with high biodiversity.” Meanwhile, as of 2002 “we appropriate over 40% of the net primary productivity (the green material) produced on Earth each year (Vitousek et al. 1986, Rojstaczer et al. 2001). We consume 35% of the productivity of the oceanic shelf (Pauly and Christensen 1995), and we use 60% of freshwater run-off (Postel et al. 1996). The unprecedented escalation in both human population and consumption in the 20th century has resulted in environmental crises never before encountered in the history of humankind and the world (McNeill 2000). E. O. Wilson (2002) claims it would now take four Earths to meet the consumption demands of the current human population, if every human consumed at the level of the average US inhabitant.” And finally, 30% of African elephants have been lost in the last 7 years.
  • Car accidents are the leading cause of death for children ages 5 to 24. The obsession with car seats may not be saving all that many lives, while keeping children out of cars as much as possible would be 100% guaranteed to save lives. And one thing that would be guaranteed to help us create more walkable neighborhoods and therefore save children’s lives: getting rid of minimum parking requirements in cities once and for all. And yet you don’t hear this debate being framed in moral terms.

3 most hopeful stories

3 most interesting stories

  • Monsanto is trying to help honeybees (which seems good) by monkeying with RNA (which seems a little frightening). Yes, biotech is coming.
  • Some people think teaching algebra to children may actually be bad. Writing still seems to be good.
  • There have been a number of attempts to identify and classify the basic types of literary plots.

minimum parking requirements

Here’s a short, visually engaging video about the problem with minimum parking requirements. Apparently, this worked in Ottawa. I don’t want to be cynical, but I am not convinced the residents, politicians, and bureaucrats of my town would respond similarly to such a logical argument. I would love for everyone to prove me wrong.

autonomous vehicles and suburban sprawl

Planetizen says autonomous vehicles won’t lead to more sprawl.

While we recognize the synergies AVs have with transit (something that is likely to be impacted by the technologythat we will discuss in the future), we do not share the belief that AVs will cause a new, unprecedented wave of sprawl. Rather, growing patterns of sprawl and longer “super-commutes” are unlikely outcomes of AVs for three key reasons: 1) the presence of existing land use, transportation, and infrastructure controls and growth management plans; 2) trends in housing consumption and residential preferences; and 3) social dynamics and the emergence of more informed decision-making.

I think the biggest effect of autonomous vehicles within urban areas will be on parking. At the moment, we have enormous numbers of parked vehicles taking up enormous amounts of space right where we are trying to live, work, and shop. With autonomous vehicles, we should either be able to share them, meaning a smaller number of vehicles in motion more of the time rather than parked, or if we really still want to own them, they can go park themselves in out-of-the-way places and come get us when we call them. This could lead to some very vibrant, social, creative, green urban areas.

I can also imagine some people will choose to live completely cloistered lives where they are sitting in comfortable vehicles several hours a day while going to and from work, or going to far-away vacation homes on the weekend. You could even imagine people choosing to live full-time in autonomous RVs.

public buses vs. Uber Pool

This article talks about the idea of shifting from public bus systems to Uber Pool, and comes out against it.

Uber Pool’s cost disadvantage over public transit might disappear if a new pilot program in Boston catches on. This month, Uber announced that it would introduce monthly Uber Pool passes—like transit passes—for just $2 per ride, or less than the MBTA’s $2.25 fare. While these temporary low fares are no doubt a money-losing loss leader, if UberPool fares are anywhere close to the price of public transit it would seem like we’re probably looking at a massive shift from public transit to these sorts of ride-hailing services. And wouldn’t that be a good thing, if it’s both faster and nearly as cheap?

But here’s where the importance space-efficiency comes in. When one person switches from the bus to Uber, two things happen. One is that they get a faster trip almost by definition: A vehicle that makes many stops (the bus) is going to be slower than a vehicle that makes few or no stops (the Uber) unless the bus has some other advantage, like transit lanes that allow it to avoid traffic congestion. And the vast majority of American bus lines are given no such benefit.

The second thing is that they switch from a very space-efficient vehicle, where they probably take up only a few square feet on the road, to a very space-inefficient vehicle, where they take up many, many times more.

It seems to me there is a middle ground here. A technology like Uber Pool, whether in private or public hands, could put the right size vehicles on the right routes at the right times. On some routes at some times, that might be a golf cart, and at others it might be a double decker bus. A system like this could be very flexible and adaptable.  Of course, using our own muscle power for as many trips as possible is also an important part of the equation and if we really want to be sustainable we need to design our towns and lives so that is the best choice for the majority of our daily trips. Communication technology and even virtual reality are another part of the equation because they could allow us to have the personal interaction we need in our work and social lives without physical distance being a factor.

green space and mental health

Here’s a new study on green space and health, based on the large-scale nurses’s study. One interesting finding is that mental health explains around 30% of the total benefit.

Exposure to Greenness and Mortality in a Nationwide Prospective Cohort Study of Women

In models adjusted for mortality risk factors (age, race/ethnicity, smoking, and individual- and area-level socioeconomic status), women living in the highest quintile of cumulative average greenness (accounting for changes in residence during follow-up) in the 250m area around their home had a 12% lower rate of all-cause non-accidental mortality (95% CI 0.82, 0.94) compared to those in the lowest quintile. Results were consistent for the 1,250m area, although the relationship was slightly attenuated. These associations were strongest for respiratory and cancer mortality. Findings from a mediation analysis suggest that the association between greenness and mortality may be at least partly mediated by physical activity, particulate matter less than 2.5 micrometers, social engagement, and depression.

fire trucks

I want to start this post by thanking the fire department for what they do. Obviously, they save lives and property, and have one of the least morally ambiguous jobs out there. That said, they are so almost universally revered that you wonder if it is okay to voice any doubts about the way they do things. So I was surprised to see this article voicing some of my own questions about whether fire trucks need to be so big. When I lived in Singapore, I noticed that they didn’t use the huge fire trucks – they were more like vans, and used some kind of foam rather than pure water. Now, the buildings in Singapore are almost all very modern, and all have prominent water hookups, and streets are very wide. Singapore chose to bulldoze a lot of its older buildings and streets at some point and start fresh, and I would not necessarily want my home city of Philadelphia to do that – I love our narrow streets, largely 19th century housing including my own house, and the walkability, mom-and-pop businesses and odd scattered public spaces it leads to. Another thing is that as an engineer occasionally involved in aspects of street design, the fire department is sometimes a voice in opposition to change. Take bumpouts for example that create  a shorter crossing distance for school children at intersections. These will save lives. The fire department will say that these slow down fire trucks making turns, and anything that slows down fire trucks could cost lives. I am not saying this is the wrong dialog to have, but the fire department shouldn’t always be the bullies getting their way, the two safety issues should be weighed against each other and a rational (okay, at least political) decision made.

January 2016 in Review

I’m going to try picking the three most frightening posts, three most hopeful posts, and three most interesting posts (that are not particularly frightening or hopeful) from January.

3 most frightening posts

  • Paul Ehrlich is still worried about population. 82% of scientists agree.
  • Thomas Picketty (paraphrased by J. Bradford Delong) says inequality and slow growth are the norm for a capitalist society. Joseph Stiglitz has some politically difficult solutions: “Far-reaching redistribution of income would help, as would deep reform of our financial system – not just to prevent it from imposing harm on the rest of us, but also to get banks and other financial institutions to do what they are supposed to do: match long-term savings to long-term investment needs.”
  • Meanwhile, government for and by big business means the “Deep State” is really in control of the U.S. In our big cities, the enormous and enormously dysfunctional police-court-prison system holds sway over the poor.

3 most hopeful posts

3 most interesting posts

  • There are some arguments in favor of genetically modified food – they have increased yields of some grains, and there is promise they could increase fish yields. 88% of scientists responding to a Pew survey said they think genetically modified food is safe, but only 37% of the U.S. public thinks so. In other biotech news, Obama’s State of the Union announced a new initiative to try to cure cancer. In other food news, red meat is out.
  • Not only is cash becoming obsolete, any physical form of payment at all may become obsolete.
  • The World Economic Forum focused on technology: “The possibilities of billions of people connected by mobile devices, with unprecedented processing power, storage capacity, and access to knowledge, are unlimited. And these possibilities will be multiplied by emerging technology breakthroughs in fields such as artificial intelligence, robotics, the Internet of Things, autonomous vehicles, 3-D printing, nanotechnology, biotechnology, materials science, energy storage, and quantum computing.”