Tag Archives: urban planning

We want walkable neighborhoods…with big houses, big backyards, driveways, garages, and free parking

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Survey after survey shows a shift in favor of Americans saying they want to live in walkable communities.

Nearly two-thirds (64%) of respondents said they would pay more to live within walking distance of parks, shops, and restaurants, according to the latest Community and Transportation Preference Survey from the National Association of Realtors®—shared first with Realtor.com®.

But intelligent people who probably did just fine in geometry in high school do not connect what they learned to the two-dimensional reality of their neighborhoods.

But enthusiasm drops when walkability becomes a question of what gets built nearby. While 63% say small-lot single-family homes would be a good idea in their community, support falls to 51% for townhomes, duplexes, and other attached housing, 44% for rental apartments, and 40% for condos.

When you set up the geometry that includes those large lots and lots of car storage storage space both at peoples’ homes and nearby shopping centers, the car infrastructure ends up taking up a lot more space than the actual houses, yards, and stores. Things get more spread out and quickly become unwalkable.

There are some potential solutions I can think of. Mixed use (commercial and residential together) is the obvious one. But people have at least an impression that this means more crime and noise. Setting up cities in a more linear way is a possibility – a long, narrow commercial main street with a long, narrow strip of housing behind it including single family homes and lots if that is what people want. Safe, protected infrastructure for bikes, scooters, golf carts, and whatever light low-momentum vehicles we come up with next – these let you cover those distances that take too long or are too boring to walk. Maybe they need to be covered in some climates. But most importantly, there has to be a safe, protected middle ground for light, practical transportation modes that fall in between walking and heavy highway vehicles. And the resistance to this basic concept is just enormous, for some reason.

Traditional public transportation definitely should play a role, particularly along that linear main street. But when things are more decentralized and randomly laid out, vehicular transportation may need to be more on-demand, whether public or private, human driven or autonomous, and I think we should just experiment with all combinations of these until we figure out what works for a particular community. If we can decouple the need to get around in vehicles from the need to store all those vehicles in a stationary manner steps away from our homes and businesses, that can free up a lot of space.

I can picture all this in my head just fine, and then the painful process of change on the ground is measured in decades if not generations, so now at age 50 I wonder if I will see a freaking safe protected bike lane in my neighborhood during my natural lifetime (and my neighborhood is one of the most walkable neighborhoods in one of the most walkable cities in the USA!).

Urban greening roundup

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I have a bunch of urban planning, urban greening, landscape architecture and engineering journals in my RSS feed. Sometimes a lot of time goes by in between articles that I find interesting. But today an interesting cluster popped up, so here are a handful of highlights. The words below are my musings, not necessarily a summary of the papers. Click through if you are interested.

  • From Landscape and Urban Planning, Intensifying drought threatens the heat-regulating capacity of urban vegetation: Trees, parks, and soil cool cities through both shade and evapotranspiration. But for evapotranspiration to work and for the vegetation to persist long-term, there has to be water. There are going to be some areas where there is not enough water in an absolute sense, and others where there is enough water in a year-round water balance sense, but it is not stored during wet periods and provided to the vegetation during the dry periods in between the wet periods. Then there will be some lucky areas that are both hot and have plenty of water most of the time, although even there you may have an infrequent drought severe enough to kill vegetation without irrigation.
  • From Earth’s Future, Urban Landscape Irrigation and the Future of Sustainable Cities: Compared to agriculture, irrigation in urban areas is very ad hoc and not very scientific. Beyond that, and I don’t know whether this article gets into it, a lot of irrigation is done with drinking water. In an ideal world, you would capture every drop of rainfall and use it for something useful. You would deliver and use drinkable water in homes and businesses as efficiently as practical, and treat the resulting wastewater only to the state necessary to use it for irrigation. Then you would theoretically irrigate only at the rate of evaporation. All this requires a level of plumbing and real-time control implemented in a million decentralized locations with different owners/stakeholders and different types of land use. Maybe some sort of positronic brain could help, but it’s a heavy lift in the near-term.
  • From Urban Forestry and Urban Greening, Assessing patterns and gaps in recent urban nature and biodiversity planning across 25 European cities: The European Union has taken a heavy-handed regulatory approach as it tends to do, requiring urban areas to develop and submit “Urban Nature Plans” for approval. This appeals to me as a proponent of both planning and managing urban ecosystem service provision. I like the idea of weaving green infrastructure planning into the bigger picture of urban infrastructure planning, then tying public infrastructure funding to implementation of projects that are consistent with the plan, particularly in times when private-sector growth slows down and there is a consensus that government economic stimulus is needed. This is all rational, evidence-based, and non-partisan in my mind. I also recognize it is nowhere near politically viable in the near term in the United States or oh-so-practical developed Asia, let alone developing countries.
  • From Trends in Ecology and Evolution, The carbon cost of forest fragmentation: Size matters: In my fantasy world of rational policies and plans, we can start thinking both about total habitat and habitat connectivity within and across cities. Here is some evidence that connectivity has a multiplier effect on carbon sequestration that goes beyond just size. It makes sense, if vegetation around the edges of habitat tends to be more stressed and less productive. Of course, there is a longstanding debate about the relationship between productivity, and biodiversity or habitat quality. An algae bloom or a hillside covered in kudzu is pretty productive, for example, and the opposite of biodiverse.
  • From Ecological Engineering, Assessing the role of wildlife ecological corridors in restoring functional connectivity of road-fragmented habitats using a stochastic movement model and scenario simulation: There is a fair amount known about corridors and connectivity, although not so much in urban environments. (I don’t normally toot my own horn, but since this is really something I have looked into that many others have not, feel free to have a look at Chapter 6 in my dissertation. No pressure. Some day I would love to distill this into a concise seminal academic paper, but I don’t have the bandwidth or library access these days.) People are starting to use agent-based, stochastic simulation in addition to older approaches based mostly on static land use/land cover analysis, which I find interesting.

pedestrian level of service

I had actually never heard of pedestrian level of service, but it appears to be just applying traffic flow modeling principles to pedestrian flow. It is intuitively appealing to me because you can just add pedestrians, cyclists, or whatever mode you want to a transportation model and specify which links in the network are open to which types of “traffic”. Theoretically, you could try to optimize the total flow of people from where they live to the places they need to get to, and not just maximize the flow of motor vehicles. Surely someone must have looked at this. A valid criticism, of course, is that these models can be short-term focused, even looking just at a single weekday peak hour and certainly missing longer-term dynamics like how infrastructure capacity and land use policy affect trip generation over time. Another criticism is that this engineering approach completely misses the quality of life aspects of urban design.

Pedestrian infrastructure assessment: Walkability vs. pedestrian level of service

This paper explores two of the most explored indicators for evaluating pedestrian infrastructure: walkability and Pedestrian Level of Service (PLOS). Walkability, typically used by urban planners, emphasises the qualitative aspects of the built environment, such as safety, comfort, accessibility and aesthetics, whereas PLOS, primarily employed by transport engineers, quantifies the operational performance of infrastructure based on pedestrian flow, density and speed. A systematic PRISMA-based literature review was conducted, covering 60 PLOS studies and 55 walkability studies were analysed in terms of definitions, contributory factors, data collection methods and modeling techniques. Despite sharing the goal of promoting pedestrian-friendly environments, these frameworks differ fundamentally in scope, purpose and methodology and are often applied independently. The findings indicate that walkability indicators vary in how factors are measured and allocated across dimensions. Moreover, walkability is treated as a “static” factor, both conceptually and methodologically. Relatively limited research examines how walkability changes over time (e.g., day vs. night) or varies across population groups. Conversely, PLOS generally excludes socio-spatial dimensions, a choice consistent with its original purpose rather than a methodological limitation. Some approaches attempt to incorporate subjective factors, but usually in ways resembling traditional walkability metrics. This study highlights the need for greater standardization in definitions and assessment frameworks, while also identifying challenges that complicate their practical applicability. Their complementary use can significantly enhance the design, evaluation and planning of pedestrian infrastructure, supporting more livable, sustainable and inclusive cities.

Will autonomous vehicles increase congestion?

Yes, autonomous vehicles will increase vehicle miles traveled by about 6% according to at least one set of serious researchers. They say this might not sound like much, but it will be enough to exceed capacity and cause massive traffic jams. Now, I’m sure these are serious transportation researchers who have thought about all the things I mention below, but I’ll mention them anyway:

  • Autonomous vehicles shouldn’t need to maintain the same “safe following distance” human drivers are supposed to maintain, which is based on slow human reaction times. So the autonomous vehicles should be able to travel closer together (from front to back) than human drivers at a given speed, and do this safely.
  • They also should be able to travel closer together from side to side. Our standard 12-foot travel lanes allow a lot of space for human drivers to weave wildly and unpredictably from side to side, which of course we do. Keep your arms, legs, heads, and pets inside the vehicle at all times, please!
  • Most vehicles are parked most of the time, so that much more space is required for vehicle storage than for moving vehicles. Not only this, but enormous amounts of empty space are required between parked vehicles for human drivers to maneuver the vehicles in and out of storage. Computers drivers will need much less space for maneuvering and will be infinitely patient.

So put all this together and I think that even if VMT increases, the amount of physical space required for vehicles could be massively reduced. This could be a big win for people, cities, and the environment. If VMT increases because people are able to get around more easily and cheaply, including the elderly, disabled, and parents pushing strollers, in all kinds of weather, this is a win for quality of life. I don’t see artificially restricting mobility as a win for people. I shouldn’t even have to say that reducing death and injury caused by vehicles by a factor of 10 or more is a moral and quality of life win.

Now, I am worried about urban and suburban sprawl getting even worse as it gets easier to get around. I am worried about air pollution and climate change. Add in augmented and virtual reality, and we might also come to care less and less over time what our cities look like to unaugmented eyes. I love compact, walking, cycling, and public transportation oriented urban form. One of the downsides of this form in the past has been a lack of green open space, but massively reduce the amount of space required for parking, and it will open up a lot of space in cities that we will then have choices of what to do with. So it really comes down to policy choices, and different places are going to make different choices, but I don’t see the technology itself as the root problem.

habitat area and fragmentation

I gave a talk this week on a niche topic involving plant selection for stormwater management features like rain gardens in cities. I had just one slide on habitat connectivity and fragmentation as an interesting area for further research. That one slide generated a lot of interest. And it is an interesting topic. First of all, it has been looked at quite a bit in the design of nature reserves, but not so much in urban areas or areas with a mix of wild, agricultural, and urban land uses. And second, there is always the debate about whether focusing too much on connectivity metrics can detract from just preserving enough total habitat. The article below is an entry relevant to this question, relevant in the context of forests. In urban areas, in my view, this question gets flipped on its head. Fragmentation and disconnection is the de facto state, and can only be reversed on the margins. So the interesting question to me is what policy choices can make it the least bad. There is also the possibility that better policy choices in urban areas can reduce friction of (animal and plant) movement between wild landscapes, and even whether they can serve as relatively biologically functional islands in depleted agricultural landscapes.

Why controlling for habitat amount is critical for resolving the fragmentation debate

The need for a consensus on the effects of fragmentation per se is increasingly recognized (Miller-Rushing et al., 2019; Riva, Koper, et al., 2024; Valente et al., 2023) because deforestation continues and small forest patches are particularly vulnerable to destruction (Riva et al., 2022). If fragmentation per se reduces biodiversity, then policies should prioritize protection and restoration of large patches. If not, then policies should include all forest, irrespective of patch sizes (Riva & Fahrig, 2023). This would allow effective biodiversity conservation, even in human-dominated regions where no large patches remain, by protecting and restoring sufficient forest over a network of many small patches (Arroyo-Rodríguez et al., 2020).

U.S. transportation “wins” in 2025

Bloomberg has an article on progress in U.S. transportation policy and technology in 2025. My thoughts in brackets.

  • New bus lanes in a number of U.S. cities. [This is really a big win, when modern cities around the world are expanding subway and light rail networks? This “win” represents tiny, incremental progress or holding the line in our current reactionary cultural and political climate. Calling this a win is a pretty good indicator of where this climate stands.]
  • New York City congestion pricing. [This is an evidence-supported, objectively very good policy that probably all major cities should be following. The fact that one major city is able to do it against massive external opposition is an indication of our current reactionary cultural and political climate. One thing that makes this work in NYC, I believe, is that they have one municipal transit agency in charge of roads/streets/bridges, public transportation, and parking, and they also have a successful and powerful interstate transportation commission that coordinates well with that agency. I’d like to see some journalism on what the legislative and institutional barriers are to achieving this in other major cities, even if we were to eventually emerge from the current reactionary cultural and political climate. For example, in Philadelphia we have a state-chartered regional public transportation authority that operates buses, subways and trains; another interstate commission that operates bridges and some trains; a neighboring state-chartered authority that operates some buses and trains; a municipal authority (which has been state-controlled in the past) that regulates street parking and parking garages, and a municipal transportation department that designs/constructs/maintains most streets, although some streets are designed/constructed/maintained by the state transportation department. All these entities are mostly uncoordinated and certainly do not share revenue. So it would be virtually impossible to use parking and bridge toll revenue to cover public transportation costs, even though this would make total sense if the objective were to move people from point A to point B efficiently, safely, and cheaply. (Would this not be the objective of any rational transportation policy?) Could all these agencies be reorganized to look more like the NYC system? Planning and implementing something like that would be a heavy lift, but again I would like to know if it would even be legally possible or if legislation at the state level in multiple states would be required. State-level legislation in Pennsylvania to rationalize policies in the major metropolitan areas is virtually impossible in the current reactionary cultural and political climate…]
  • Automatic speed controls in cars. There are some minor wins allowing judges to impose this on people who have speeding tickets. This makes sense to me, but seems fairly small and incremental. I might be the only one looking forward to automating as much vehicle operation as possible. Let violations of speed limits and intersection signals be matters for your vehicle warranty or insurance company, not decisions of human drivers to take reckless risks or not.]
  • Legalizing small cars and golf carts on public streets. [I’m mostly for this. Vehicles designed for highway travel are the wrong way to get around inside cities. The problem is that you put these lighter vehicles on the public streets, and human beings in them are going to be hurt and killed by other human beings choosing to irresponsibly operate highway vehicles inside cities. They will also hurt and kill pedestrians on occasion. You need to either have separate infrastructure for the light vehicles, or have vehicles regulated or controlled by computers or passive means (see above). Advances in street design, construction and maintenance in the U.S. are so slow I find it hard to hold out hope that there will be big changes in the course of a single generation of humans. But technology is moving much faster so I am going to put more of my hopes for near-term progress in the technology basket.]

So there it is. I don’t have much hope for seeing widespread progress in subway, light rail, and modern street design and construction (with separate infrastructure and signals for pedestrians, light vehicles, and highway vehicles) in U.S. cities in the next few years. We can hope for slow, incremental progress on congestion pricing, parking pricing and policy, and passive speed controls for some vehicles. The rollout of automated, electric vehicles has been slower than I might have predicted 5-10 years ago, but it is happening. It is uneven because the barriers seem to be more legal/institutional/cultural/political than technological and this varies by location. And it’s not a straight-up red/blue divide because pro-big-business forces on the right are favoring automated vehicles at the same time reactionary cultural/political forces on the right and pro-labor forces on the left are opposing them. So this tension will just play out state-by-state and city-by-city for some time to come. Very slowly, we may realize that the demand to devote so much of our urban space to parking and maneuvering inefficient vehicles has decreased. This feels like it might take a decade or more and be obvious to most people only in retrospect. Overall, when Americans travel I think we will increasingly get the sense that urban conditions in our country are continuing to stagnate while European and Asian cities march into the future. Those of us Americans who don’t travel will be cocooned in reactionary cultural/political propaganda and will not realize life is improving elsewhere while transportation in our cities is stuck at a 1970s technology and safety level.

May the streets of our cities be soaked with less blood in 2026 and beyond!

medieval French towns

This (paywalled) Financial Times article has eye-popping pictures of French towns built in the 1200s and 1300s. Many of these still exist and are going strong today, and people love them. They were small (around a thousand people) and densely populated. They were generally built around a public square with a weekly market. At the time, the article says, feudal lords created the towns as a way of concentrating, controlling, and taxing people, in exchange for greater safety and quality of life. The feudal lord generally owned the commercial and industrial real estate, of course, but the article says this can be a model for development corporations today, with master planning and long-term ownership of business districts. Housing developers in theory can do their short-term thing but pay into these development corporations which are then set up in perpetuity to operate and maintain the commons. Sounds good in theory. Clearly the private markets don’t create the kind of green spaces, schools, etc. that people say they want but then vote against with their actual dollars and housing and transportation choices.

Lussan, Département Gard – aerial view

the problem with sprawl

This article from Strong Towns has a good explanation of why low-density development is not the answer to the housing supply issue.

this style of development works extremely well for a specific type of private developer… developers like Ross Perot Jr. are masters of the assembly-line approach: secure cheap land on the fringe, install infrastructure, and build tract housing as quickly as possible. At this scale, the profits are enormous, and the risks are low. The federal government provides generous support through mortgage guarantees, tax preferences, and highway spending, and buyers keep lining up for new homes.

But while the private sector gets the cash, local governments get the bill. Sprawling developments create long-term infrastructure liabilities—roads, water lines, sewer systems, schools, fire protection—that far exceed the revenue they generate. Local governments, which are really just collections of us acting together, are left trying to maintain and operate systems that are fundamentally unaffordable.

As Mayor Eugene Escobar of Princeton, Texas, put it, his town boomed with affordable homes, but now it’s struggling with traffic, overburdened infrastructure, and a lack of basic amenities. The city’s leadership is trying to build a real downtown, attract jobs, and create public spaces—but they’re doing it after the fact. That’s not planning. That’s triage.

Some suburbs seem to persist for long periods of time. But they are ones located within commuting distance of urban centers with high-paying professional jobs, and the zoning serves to keep the median income in those successful suburbs very high, and therefore able to support the very high infrastructure costs per resident or per square mile. There aren’t enough of these highly affluent people for all suburbs to work like this, so for every successful one there are many turning into slums.

What seems to be suggested instead is a gradual process of intensification from the middle out, so that populations, incomes, and tax revenues can keep rising over time as value is continuously created. This makes sense to me. I think there may be a more linear model though that could work for U.S. suburbs, where the intensification happens along a transportation corridor with progressively less dense development as you move back from highway. This way, you get a long linear downtown with access to transportation and other infrastructure at a low unit cost. People could live in relatively low-density neighborhoods if they want to and still not be too far from work, school, and inter-city public transportation. And these commercial corridors already exist in the form of arterial highways, water and power lines, big box stores and car dealerships separated by oceans of parking.

April 2025 in Review

Most frightening and/or depressing story: Maybe an irreversible methane tipping point is happening. This could be the scariest thing out there short of nuclear war.

Most hopeful story: 3-30-300 is a nice, simple idea. “you can see 3 trees from your window, your neighborhood has 30% tree canopy cover, and you are within 300 m of a half-hectare park.” Sure, you have to figure out some details and make some sustained effort over time to implement simple ideas. Still, not rocket science. Combined with the “15 minute city”, this is a pretty good urban planning philosophy that should be communicable.

Most interesting story, that was not particularly frightening or hopeful, or perhaps was a mixture of both: I made what I would consider a “common sense” trade policy proposal. “I generally support…free trade. But if we are going to trade freely, we need a safety net for people who are hurt. We could do this with generous unemployment benefits and retraining programs. We could help people relocate to places with jobs. We could provide much better communication and transportation infrastructure allowing them to commute regionally to places with jobs. We could educate their children so they are prepared for the jobs of tomorrow. We could institute a value added tax on our productive, growing economy and use it to provide services or cash to workers. We could invest even more in research and development to make our economy even more productive and growing. We could invest in neighboring countries to help them be more productive and growing, import cheap stuff from them, and reduce some of the migration pressure on our borders.”

https://homertree.com/blog/the-3-30-300-rule/

Planetizen’s top posts of 2024

There are a lot here. Quite a few have to do with housing, a topic I would be interested in brushing up on. A lot have to do with transportation, a topic I have just feeling complete and utter despair about, at least in the context of the United States and my particular city and state. One possible bright spot is congestion pricing in New York City. Congestion pricing just works, even though it is politically unpopular and counter-intuitive to many people’s “common sense”. Maybe people will notice that it solves some of the congestion and parking issues they like to complain about, and maybe it will slowly spread to other cities and states.