Human Transit

my friendly advice for developers

The Urban Land Institute has an interview with me today, where I chat through some of my friendly and supportive to developers when thinking about transit.  

(Short version: Read my book!  Take my course!)

shared housing and shared transportation (guest post by alfred twu)

Alfred Twu lives in the Bay Area and is a long time transit rider.  He has studied architecture and business and is also an active participant of the cooperative movement, having worked in artist, food, and housing co-ops. He is also an illustrator for my forthcoming book Human Transit.

Also known as cooperative living, co-ops, communes, intentional communities, or living with roommates, shared housing creates challenges and opportunities for transit service.  It can increase density without zoning changes or construction.  However, good transit service needs to already exist for this to happen.  As such, shared housing's greatest potential is in increasing utilization of under-zoned but well served neighborhoods. 

What is shared housing?

Shared housing denotes a group of unrelated people live in a single dwelling unit.  Kitchens, bathrooms, and other living areas are shared, bedrooms may be shared or single occupancy.  In the Bay Area, this model is known as a co-op or cooperative.  Note that the word co-op has an entirely different meaning on the East Coast.

Shared housing has a long history in the Bay Area, dating back to boarding houses.  The modern Bay Area cooperative housing movement began in 1933 with the founding of the Berkeley Student Cooperative. 

Although some structures are built with shared housing in mind, usually the building is simply a repurposed large house.  For example, Ridge House, a 38 person student co-op, used to be a mansion, while Cooperative Roots, pictured below, houses around 20 people in two adjacent single family houses.




What does this have to do with transit?

Let's look at two neighborhoods: one dense, and one sprawling.  The denser neighborhood will usually have better transit service.

Now, if zoning ordinances prevent additional housing from being built in Sprawlville, that does not mean it's the end of the story.  While zoning typically concerns itself with units per acre, the density that matters for transit service is population per acre, or more specifically, commuters per acre.

This is where shared housing comes in.  When a neighborhood of single family houses goes from having one or two working adults per house, to having 4 to 8 working adults, as far as transit is concerned, it's a high density neighborhood.




The catch to this though, is that this can only happen where there is already good transit service.  When a group of people share a house, they'll all want easy access to their jobs, which may be in different directions.  Not all of them will take transit either - some of them will need to drive to their jobs, some people prefer to bike.  This is why shared housing works so well with college students - everyone is going to the same place for their "job", so only one frequent route is necessary.

Case Study: Ashby BART  (San Francisco Bay Area)

A number of my friends who used to live in shared housing as students have formed their own communities after graduation.  Most are now in their mid 20s to early 30s.  Some work office jobs with traditional 9-5 hours, others work retail jobs with varying hours.  Over the last few years, about 30 communities of 4 to 18 people have been formed.  Most cluster around the Ashby rail rapid transit station.  Let's examine why.

• It is about halfway between the two big job centers in the area: UC Berkeley and Downtown Oakland.
• It is 20 minutes on rapid transit to the region's largest job center, downtown San Francisco.
• It is close to freeway on-ramps.
• It is on flat ground and within biking distance of a large number of commercial districts.  Bike access is important since transit service in the evenings and on weekends is limited.
• It is not in itself a downtown district.  This means there are a lot of large houses with lots of bedrooms and yards - the preferred housing type.
• There are already other co-ops in the area.

The one co-op not near a BART station -- an outlier near the bay -- is an artists' warehouse.



Ashby Station: Excellent transit service but low density

The Ashby station neighborhood, which currently consists of mostly single family houses, had long been targeted by planners for transit oriented development.  It has an underground rapid transit station with train frequency of every 7 minutes on weekdays and 20 minutes at night and on weekends.

Ashby station neighborhood.  Station is blue, parking lot is black.


However, the official plan to build 300 units of housing on the station parking lots met significant neighborhood opposition.  Existing residents were concerned about losing the flea market that currently operates on weekends in the parking lot, increased traffic, and future upzoning of the area.  The project was put on hold in 2006. 

Shared housing, however, has achieved something similar with no official intervention.

Can the Ashby model be replicated elsewhere?

Using shared housing to increase neighborhood density offers a solution for low density areas where economic constraints or zoning limits the ability to build new housing units.  The following factors are needed for its success:

Multimodal Job Access

Members of a shared house with long commutes tend to move out.  Therefore a location needs good access to members' existing jobs, and potential future ones.  Transit is just one part of the equation - those working 9 to 5 hours downtown.  For the other members, good car and bike access to nearby commercial areas is needed for those working retail and service jobs on evenings and weekends. 

Catalyst community and clustering effect

The Ashby area community began with just a couple of houses.  However, the community grew rapidly as the original residents' friends also wanted to live nearby.  UC Berkeley provided a feeder system with many members having already familiarized themselves with shared housing through living in the Berkeley student co-ops.  In places far from colleges, immigrant neighborhoods can also benefit from the feeder effect.

One of the side benefits of shared housing is a group of residents will have a lot of purchasing power with their combined incomes, and will seek out the area that meets their needs best.  Until most people live in shared housing, this means that a region will likely have only a small number of preferred neighborhoods.

Why not MacArthur?  Station placement matters.

The next station down the line, MacArthur, is even better positioned in terms of access to transit and jobs.  However, this station is located in a freeway median.  As a result, a lot of the land walkable to the station is either paved over, or so close to a freeway that it is an unpleasant place to live.  As a result, even though this area has been zoned for multistory apartments, few have been built.

Creating community: the station as social hub

Shared housing in the Ashby area occurred without any official planning - an existing community (recent UC Berkeley graduates) simply moved in.  Where no existing community exists, social hubs such as coffee shops or community centers, located inside or directly next to the station, can aid the formation of the close relationships that shared housing requires.

should inaccessible employers subsidize transit?

Lisa Margonelli has a nice short piece in the Atlantic today on the sustainable transport achievements of Bishop Ranch, an enormous business park in suburban San Ramon east of San Francisco. 

The park was developed from farmland by Masud Mehran's Sunset Development Corporation in 1978 on the belief that San Francisco real estate would soon become expensive and companies would need cheaper space for their administrative services. His grandson, Alexander Mehran, describes the transit program as "a necessity that developed into a whole different animal." When the park started, it was simply too far from anywhere. "We were getting crushed by people going to work in Walnut Creek and Dublin," where the BART stations are. As a result, the ranch bought a fleet of buses and worked with the city and county transit agencies to subsidize both bus routes and bus passes for workers. There are now 13 different bus routes running to the park, and the connections to BART and various local train and express bus services are coordinated. On its website, the Ranch now pitches its transit program as a competitive advantage.

The most important word in that paragraph, of course, is subsidize.  Suburban business parks are expensive, per customer, for transit to serve, so a suburban employer can't expect attractive or useful service simply by demanding it.

The second most important word is cheaper, which in the suburban context is sometimes an illusion.  Bishop Ranch exists because it was perceived as a cheaper location for business.  It is, but partly because land value follows access.  The cheapest site will usually be the one with the worst transportation problems, and if a business chooses the site solely on those grounds, they're transferring the hidden cost of transportation onto their employees, their customers, and the transit agency.  Employees can quit, customers can go elsewhere, and increasingly, transit agencies, too, are pushing back against serving these cheap-because-inaccessible sites, by suggesting that employers take responsibility for some of the cost burden created by their choice of location. 

Finally, it's worth noting that Bishop Ranch is a fairly intense business park, with many multi-story buildings.  Effectively it was a single-use new town of considerable density, so while the location was difficult for transit, transit agencies still had a ridership motive in serving it.  If it were being built today, I hope Bishop Ranch would be mixed-use, with some residences mixed in, and also located with greater care in relation to existing and potential transit corridors, on the "Be on the Way" principle.  Still, for being what it is, Bishop Ranch deserves a lot of credit for taking responsiblity for the transit consequences of its site, and investing in services to help overcome those barriers.

will car-dependent development have resale value?

Well, sooner or later, you'll have to sell to the next generation, so it makes sense to be paying attention to what they think. 

transit's role in "sprawl repair"

Duany Plater-Zyberk, one of the leading planning firms associated with New Urbanism, is thinking about "sprawl repair," a process by which utterly car-dependent landscapes could be transformed into something more walkable, and thus more resilient.  Galina Tachieva of DPZ has an article explaining the concept at Planetizen. 

The only valid option is to repair sprawl – to deal with it straight on, by finding ways to reuse and reorganize as much of it as possible into complete, livable, robust communities. Pragmatism calls for the repair of sprawl through redevelopment that creates viable human settlements, places that are walkable, with mixed uses and transportation options.

As examples, Tachieva suggests turning a shopping mall into a complete mixed use town center, or dropping townhouses into the spaces between McMansions.

The ideas she presents are exclusively about the development parcel, not the street.  Clearly, though, such urbanized places will have dramatically different transport needs, which will also require re-thinking the standard suburban arterial.  And since government has much more direct control over the street than over the development parcels, we might move faster on sprawl repair if we focused on the arterial first, or at least at the same time.  Last month, on a speaking tour that took me to Portland, Fresno and Los Angeles, I spent some time thinking about this issue.

The densified sprawl that DPZ envisions will clearly be a place that needs much more effective transit.  Parking will be more scarce, and density will be higher, so there will need to be more transport options.  While cycling will take up some of that need, transit is still the most versatile sustainable transport mode for longer trips, the only one capable of delivering you from one place to another as a pedestrian, unencumbered by a vehicle.  And the only place to put that transit, in a classic sprawl landscape, is on that huge, government-controlled arterial.

As I first discussed here, the ideal geography for transit is to have a series of transit destinations (dense housing, mixed use, jobs, activities, etc) located in what feels like a straight line, so that a transit line can connect all these points in a way that feels like a direct route between any two points.  The key challenge is to avoid slowing down or deviating too much to serve the intermediate points, as this makes the intermediate points feel like obstacles to anyone whose trip requires riding through them.

The classic suburban commercial arterial already does that, up to a point.  It gathers development around it without letting that development slow it down.  So we should be looking for ways to capture this virtue for transit.  A process of "sprawl repair" should start, perhaps, with a series of steps aimed at repairing the arterial, starting with the realisation that the arterial's straightness and speed become an asset if transit can operate reliably. 

Fresno is an interesting example because it's at a stage where it could look at what's happened to bigger sprawl-cities and choose another path.  There's not much congestion yet, partly because the city has a truly massive road network.  For a metro area of about 1m people, Fresno has three north-south freeways, one east-west freeway, and a complete grid of very wide arterials spaced about 800m apart (the ideal spacing for transit).  There is no shortage of road space for introducing new approaches to transport, and as anyone involved in struggles over bus lanes in big cities will tell you, the time to create transit priority, bike lanes, and other reassignments of road space is before the street is badly congested.

If and when California High Speed Rail opens, Fresno is going to boom.  With the Bay Area and Los Angeles suddenly less than two hours away, Fresno will be a perfect base for any kind of business that aims for a statewide market, and it will attract good employees who value affordable housing and outdoor recreation (Yosemite and Kings Canyon National Parks are both within an hour's drive.)   If HSR were there today, and I were considering setting up a consultancy aimed at a statewide market, I'd consider living there myself.

What if the city prepared for that now, by planning for the inevitable future of its abundant wide arterials?  What if Fresno's leaders went to the people and said:  "Look, HSR is coming, and our city is going to grow and change, mostly for the better.  We can resist the change, or we can get out in front of it." 

Well, you wouldn't start by proposing to build townhouses in people's back yards.  You'd start by saying: "Look, even if we boom horizontally, tearing up orchards to build more subdivisions, we'll still become more and more congested; just look at Sacramento or Las Vegas.  Eventually, we'd end up like Los Angeles, struggling with congestion that chokes the economy and constrains people's lives.  And then, we'd be desperate to get people on transit, as Los Angeles is now.  But by then, we'll have filled up our arterials with congestion, so the remaining options for building transit will be really expensive."

"What if we learned from Los Angeles's path?  Instead of waiting until it's really expensive, as Los Angeles did, what if we take early, gradual, inexpensive steps to make our arterials safe and attractive for transit?  That doesn't mean ripping up our single-family neighborhoods, but it does mean rethinking our arterials so that they're safe and attractive places for pedestrians, and so that they provide appropriate levels of priority to transit.  We don't need transit to be attractive to everyone, we're not 'forcing' people to use it, but it could attract people who already want alternatives to driving.  Let's face it, a lot of our citizens are struggling on low incomes, and cars are expensive.  Many families would experience sudden improvements in wealth if they could get rid of one or more of their cars."

"So we need to gradually repair our sprawl.  That doesn't have to mean big increases in density.  We'd build some denser centers for people who want a more urban life, but we're not going to build townhouses in your back yard -- or at least not until you and your neighbors want us to.  Mostly, we just need to stitch things together so that people can walk and cycle more safely, both to complete local trips and to get to transit stops.  It means making sure that at every transit stop, there's a protected way to cross the street, because you can't use transit for a round trip unless you can use stops on both sides of the street.  It means adding pedestrian links to cul-de-sac neighborhoods, so that they are through-routes for bicycles and pedestrians while remaining cul-de-sacs for cars.  And it means making sure that the design of bus stops and transit priority conveys a clear message that transit riders are valued as citizens, and appreciated for the contribution they make to a sustainable and functional city."

Such a pitch would need to be aimed at the practical concerns of life in a car-dependent city.  It will sound compromised and wimpy to a big-city transit advocate, but that's not who it's talking to. 

As part of my presentation for Fresno Council of Governments, I picked an arterial intersection pretty much at random and quickly pointed out all the obvious, inexpensive opportunities for sprawl repair -- not just repair of the land use, but of the streets.  Here's the intersection of Kings Canyon Road and Peach Avenue.



There's a lot to work with there.  There are already quite a few apartments, but they tend to open out onto arterials far from places where you can cross those arterials safely.  But that could be fixed over time.  With the existing development in mind, you'd identify permanent bus stop locations each of which must have a safe street crossing opportunity.  That could mean new pedestrian crossings, signalised as necessary, which could also be combined with other accesses. 

Look, for example, at the southwest corner of the image.  South of the arterial there's a patch of apartments with several possible points of pedestrian access to the arterial.  Across the street to the north is a WalMart behind a huge parking lot.   When WalMart redevelops, of course, you'd want the building brought out to the street with parking behind it, but for now I'm thinking shorter term. 

So I'd start by observing that if I signalize the WalMart entrance at the far west edge of the image, I've also signalzed a pedestrian access point to the apartments on the other side of the street.  I'm about 400m west of the main arterial intersection, so if there's a bus stop at that intersection (as there must be, because it's a connection point) then I can put another bus stop right here.  So a signal there will have three uses: (a) controlling the car access to WalMart, for safer egress, (2) providing safe pedestrian access to the apartments, and (3) providing the safe pedestrian crossing that the bus stops require. 

Once you notice this, you notice that in general, Fresno is a grid of arterials spaced 800m apart.  That means that for local service, where 400m spacing is about right, you'll have stops at the arterial intersections and then one more stop midway in between them.  Although 400m stop spacing is ideal, we can slide this intermediate stop 100m one way or the other to find the best site for a pedestrian crossing, based on the development and access points that are already there.  We can then use this crossing as a focal point when redevelopment opportunities arise on the surrounding parcels.  Over time, we'll build a more connected network for walking, cycling, and transit, without seriously obstructing road traffic.

So some principles of arterial "repair" would include:

• Put transit stops at an ideal spacing, 400m for locals, and make them permanent. 
• Require a safe way to cross the arterial at every bus stop, as a necessary condition for a stop, because you can't use a stop to make a round trip on transit unless you can cross the street there. 
• Look for a way to meet other pedestrian access needs with the same signals or crossing protections that the previous point requires.

I could also add more subjective values, such as ...

• Ensure that sidewalks along the arterial are adequate, including appropriate buffering if the arterial is fast.

... but we should pause before we go too far in this direction.  If we add too many design requirements that are derived from urbanist ideals, we can quickly lose focus on the reality of what the street is today, and the level of improvement that's needed to achieve basic safety and functionality for alternative modes.  We also risk spending so much money in one place that we can't scale our improvements to the vastness of the sprawl that needs repairing.  So when I look at a typical street intersection in typical sprawl fabric like Fresno's, I see first of all a need to create a basic pedestrian+transit infrastructure that will provide a safe and functional transit option for getting around the city.  

Once, long ago, when I was presenting a transit plan to an outer-suburban council, a council-member said: "So if we spend all this money on transit, is that going to make me leave my BMW at home?" 

The answer, from a "sprawl repair" standpoint, should be:  "No, and it doesn't need to.  Most people don't have BMWs, and many of them struggle to afford a car at all.  These improvements are focused on people who are near a decision point where transit could be a rational choice for them.  That's why our priority is basic safety, functionality, and civility.  We'll incorporate quality design wherever we can do so affordably.  But our first focus is on improvements that will scale to the size of the problem.  And there's a whole lot of sprawl to repair."

bulletin: young adults don't all want cars

A study by GWL Realty Advisors suggests that the next generation may not values cars nearly as much as the current decision-making generation does.  From Treehugger's coverage:

There is also growing research that younger generations do not relate to the automobile as enabling "freedom." Instead, their electronic and social media devices--whether a smart phone, small lap top computer, music player, etc.--provide an alternate means for self expression and being free to do what they want. In the United States, kilometers driven by 18-34 year olds is declining, and this is likely the case in Canada as well (Neff, 2010). Younger generations seem to have less interest in automotive use, making apartment living in dense, walkable and transit-oriented urban areas a more natural fit for their lifestyles.

The other day I was in Fresno, California, a city that is starting to think about denser transit-oriented development around rapid bus corridors.  Encouraging maps were being drawn, but there seemed to be a lot of doubt that bankers will ever lend for aggressive development of livable dense communities, or that developers will be courageous enough to build them.

If these bankers and developers are so smart, why are they assuming that their own preferences will also be their children's?  Many parents secretly want to see their children as perfect copies of themselves, but is the current investment paradigm really dependent on such shallow vanities?  Shouldn't they be listening to the young people who will determine the long-run payoffs of their investments?

almere, netherlands as bus-oriented development

The remarkable busway network of Almere, Netherlands is impressive from the ground, as we saw in Richard Lenthall's post, but it's even more remarkable on Google Earth:

Here is the commercial core of Almere.  (You can easily find this yourself on Google Earth or Google Maps.  Just search for "Almere, FL, NL.")

The entire image is a mile (1.6 km) wide.  Across the top of the image you can see the main intercity rail line, running east-west, with frequent electric trains to Amsterdam, Schiphol Airport (AMS), and other major towns of the country.  The station is right in the middle.

Directly south of the station is the densest part of the core, on a short axis extending south from the station to the main lake, just visible on the south edge of the image.  As you can see, a busway runs right down the middle, going underground at the station and again at the major commercial/employment center on the lake. 

Directly east of the commercial/employment center is a distinctive district with a half-circle pattern of streets.  The northern edge of the half-circle is an east-west busway.  It goes right under the commercial center and emerges on the other (west) side.  Some bus routes run east-west across this segment, but most come from the two sides and turn northward to run under the station.

Let's pan southeastward a bit, at the same scale:

The half-circle district is now in the northwest corner, where this image overlaps the previous one.  The busway branches right at the center of the half-circle.  One branch heads south, while the other continues east and then turns south near the east edge of the image.  The little Google bus stop symbols indicate the busway path, but note that not all of the bus stops appear at this scale.

As you can see, the busway is reasonably central to all of the development, because both were designed together.  At the points furthest from the busway, you have open space and a high-capacity road.  The busway brings you to central points of the community, while the road network delivers you only to the edges of it.  You can see the same pattern in the commercial core above: high-capacity roads form a ring around the core, delivering you to parking on these outer edges.  But if you come by bus, you arrive at a core location where there's very little traffic, where the walking distances to everything are optimal, and where all the infrastructure welcomes you as a pedestrian.

North Americans try hard to do "transit-oriented development," (TOD) but the Dutch are doing it on a massive scale.  Even more heretically, they do it with buses!  All of Almere is transit-oriented, and the transit is all in the form of busways.  These aren't the long-haul rapid-transit busways of Brisbane, though the Dutch do those too.  Almere's busways are designed to be the local coverage for the entire town; there's no need for additional meandering local buses getting stuck in traffic on local streets, or slowing down for the traffic-calming measures aimed at cars, such as you see all the time in North American and Australian suburbs. 

Just because service is locally oriented doesn't mean it shouldn't be as fast and reliable as possible.  Remember: average speed determines a route's cycle time, which (combined with frequency) determines operating cost.  A service that's faster and more reliable requires fewer buses to cycle, so it can be run more frequently at the same cost.

The Almere busway moves at moderate speeds and stops relatively often, but still the stop spacing has been placed as wide as possible (rarely less than 500m) and the urban form works with that spacing.  The busway intersects minor streets, but it's grade separated where it crosses a major highway (such as the top-center of the second image).  Buses are able to cycle the whole system with near-perfect reliabiilty.  The only source of delay is a problem with passengers boarding and alighting. 

The urban structure here is repeated all over the residential parts of Almere.  Explore it yourself.  Yes, you could have done this whole structure with streetcars on grass track, but for a variety of reasons, probably partly due to the ease of phasing service in, they chose to do busways instead.  You can argue over the environmental and sustainability issues of that choice.

But don't let anyone tell you that you can't build a dense and transit-oriented suburb using buses!  As always, what matters is not the technology but the mobility it's designed to provide.  That's a matter of walking distance, separation from car impacts, stop spacing, and exclusive right-of-way.  Optimize all of these, as Almere has done, and you've got an almost perfect transit system, properly located to form the primary circulation system for the community.

the perils of average density

In his 2010 book Transport for Suburbia, Paul Mees notices a fallacy that seems to be shared by sustainable transport advocates and car advocates.  Both sides of this great debate agree that effective transit requires high density. 

Sustainability advocates want higher urban densities for a range of reasons, but viability of public transit is certainly one of them.  Meanwhile, advocates of car-dominance want to argue that existing low densities are a fact of life; since transit needs high density, they say, there’s just no point in investing in transit for those areas, so it’s best to go on planning for the dominance of cars. 

Mees calls on his fellow transit advocates to let go of the idea that good transit requires high densities:

The central argument of this book is that density is not destiny.  Transport policy itself has a bigger impact on transport patterns than urban planners have realized, and suburbs don’t have to be totally reliant on the car.  Planners who insist that car dominance can only be addressed by impossibly large increases in density may actually be entrenching the problem they are trying to solve.

Transit does depend on density, but there are three problems with saying that “transit requires high density.”   

• First, it offers no hope to places that are already built at low densities and unlikely to change. 
• Second, it gives public transit in low-density areas an excuse for descending into a cycle of underinvestment, official neglect, and lazy operations, because after all, nobody expects public transit in low density areas to be any good anyway.  
• Third, it invites sweeping claims about transit’s viability based on the overall average density of a city, claims that, as we’ll see, make no sense at all.

Mees is right that “density is not destiny.”  Cities of any density can make better or worse transit choices and achieve significantly different outcomes as a result.  But density is still an overwhelming force in determining the possibilities and outcomes of transit, and we can’t begin to make good transit decisions until we understand it.

Density is hard to talk about for two reasons:  It’s very emotional and it’s hard to define and measure. 

The emotions are inevitable: Whenever we talk about urban form, people hear us making judgments about their homes.  I can stand in front of a group of citizens and talk about how a certain kind of development pattern implies certain consequences for transit, and thus for sustainability, and thus for civilization.  As we talk, it may appear that we’re having a thoughtful and educational discussion about good and bad design.  But some people in the audience have chosen to make their homes in the very development pattern that I’m describing, and to those people, I’m saying that their home is good or bad. 

Once you hear that, you’re likely to have a strong emotional reaction that makes you deaf to rational argument.  On some level, consciously or unconsciously, you’re going to feel as though I’d walked into your own livingroom and told you that your decor is not just ugly but a threat to civilization.   We all feel defensive about home.

But emotions often hide inside things that look like facts, and density "facts" are a great example.  In transit arguments, people say things like “the net density of Toronto is ###/hectare,” because this sounds like a fact and therefore conveys some authority to their argument.  In reality, though, there are several possible meanings of “density” in that sentence, as well as several possible definitions of “net” and ”Toronto.”   Briefly:

• “Density” in an urban planning context is always some kind of quantified human presence divided by some kind of land area, but it can be residential density (residents or homes per acre) or it can be total development density -- including homes, businesses, schools etc – or it can be an economic density such as the number of jobs in an area. 
• “Net,” as opposed to “gross,” means that the human presence is being divided by a smaller unit of area instead of a larger one.  In calculating the area, for example, you might take out undevelopable land, and bodies of water, and the land taken up by streets and highways -- or you might not.  There are arguments for or against excluding each of these things from “net density,” and an opinion about each of them is hiding inside the word “net.”
• “Toronto,” of course, can be the City of Toronto, or the Toronto Transit Commission area, or the whole urban mass of greater Toronto.  These obviously have utterly different average densities.

So the statement “the net density of Toronto is ###/hectare” is really as subjective as the statement “I think that cities should have more open space, narrower streets, and should have single governments covering the entire urban area.”  Because each of those opinions can affect how you choose to define “net,” “density,” and “Toronto,” which in turn determines the number that you declare, with cold factual authority, to be the net density of Toronto. 

At the core of Mees’s book, for example, is a table[1] that compares the gross residential density of a bunch of urban areas with the transit performance in each area.  The point of the table is to show that there’s really no relationship between the two.  Before we look at some fun facts from this table, remember that definitions are everything.  So in this case:

• “Metro Area” (my term for what Mees’s table calls “City”) is the entire urbanized area around a city, regardless of government boundaries.[2]  Think of it as the continuous patch of lights that you can see from an airplane at night.
• “Density (pop/ha)” is residential density – the entire population divided by the entire area. 
• “Transit work mode share” is the percentage of trips to work that go by transit, as opposed to car, walk, bike, etc.  Trips to work are not the only ones that matter, but they are the only ones that are measured in a consistent way.

So with those cautions, here’s a taste of Mees’s scandalous numbers:

Metro Area	Density (pop/ha)	Transit mode share for work trips.
Los Angeles	27.3	4.7
New York	20.5	24.8
Las Vegas	17.7	4.1
Vancouver	17.0	16.5

The density figures are calculated to shock.  Los Angeles is denser than New York?  Yes, that’s what happens when you average over a huge contiguous metro area.  Your own impression of “New York” is probably formed by the massed and soaring towers of Manhattan, but New York is a dense city surrounded by a lot of very low-density suburbs that are all included in this concept of “metro New York.”  Likewise, your stereotype of Los Angeles may be a ranch-style house with a big pool on a cul-de-sac, which implies a very low density, but in fact much of greater Los Angeles is four-story apartment buildings lined up for mile after mile.  Obviously, our impression of the density of a city is based on the part of it we choose to remember, or that we tend to see on television.  The average density of the whole urban area may be entirely different.

To me, Mees’s table proves that average density over a whole urban area is the wrong kind of density for understanding transit.   The impression you probably have of the densities of these cities is actually closer to the kind of density that matters. 

Transit reacts mainly with the density right around its stations.  It is in the nature of transit to serve an area very unevenly, providing a concentrated value around its stops and stations and less value elsewhere.  So what matters for transit is the density right where the transit is, not the aggregate density of the whole urban area. 

Of course, what matters even more precisely is how much stuff is within walking distance of a station, so it's not just density (the amount of stuff in a fixed radius) but the completeness of the pedestrian network.  A poorly connected pedestrian network can ensure that much of the stuff that's within a 400m radius is not in a 400m walk. 

Consider Las Vegas, which Mees finds to be denser than highrise Vancouver.  The Las Vegas economy is based on hospitality and entertainment, labor-intensive industries with low average wages.  So the city needs a lot of housing suited for lower incomes.  The Las Vegas way is to build utterly car-dependent apartment buildings on a vast scale, achieving all of the disadvantages of density with none of its benefits.  Consider:

For scale, the width of this entire image is about 0.55 miles, or 0.9 km.  The arterials along the south and west edges of the image are the only streets straight and fast enough for efficient transit.  Note how these large apartment developments are soundwalled from most direct access to these arterials, and how the accesses they have tend to come out at points where there's no controlled intersection, so the arterial is dangerous to cross.  (Two-way transit trips always require stops on both sides of the street, so if you can't cross the street, you don't really have access.)

So yes, Las Vegas has massive quantities of apartment buildings, which yield a high average density.  But at two levels of scale, these are deployed in patterns that make effective transit difficult.  On a macro level, Las Vegas is mostly midrise apartments spread over a large area, requiring transit to cover more distance to serve them; this is the most obvious explanation for Las Vegas's low transit performance compared to highrise Vancouver.  But the micro explanation is important too.  In the details of street pattern and pedestrian circulation, typical Las Vegas urban fabric is designed for motorists and hostile to pedestrians.  Average urban density says nothing about either of these factors, even though they are what really determine the transit experience in each city.

It's inevitable that in comparisons between cities, we're going to hear average density figures.  These figures are better than nothing when it comes to making global comparisons.  The famous databases created by Jeffrey Kenworthy and Peter Newman, for example, are useful in showing how a range of sustainability outcomes vary with density. 

But averages are dangerous, especially in transit.  Averaging sounds like a credible way to draw a simple fact out of a huge and diverse reality, but often, averages are just not the fact that matters.  In a recent post on the perils of average success, I pointed out that no transit customer really cares about average frequency, or average lateness, or average crowding.  By the same token, transit advocates need to be suspicious of average density.  What matters is the density around the transit system.  How can we best measure that?

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[1]   Fig 4.1 p 60

[2]   In the US, “an ‘urbanized area’ is defined for each metropolitan region, made up by combining adjacent ‘census blocks’ (the smallest units for which data are collected) with more than 1000 residents per square mile, or 386 per square kilometre. …  Canada defines “urban area” on an almost identical basis to the US, using a density threshold of 400 [residents] per square kilometre.”  The data is from 2006 census in Canada, 2000 in the US.

can local buses "stimulate" development?

One of the troubling side-effects of the streetcar revival movement in North America is that streetcar advocates often need to argue that buses don't stimulate development, whereas streetcars really do.  But now and then someone says something like this:

Now, in Seattle, I picked my current apartment in large part because it was right next to a trolleybus (the 44).

Frequent bus lines clearly do attract tenants and buyers to some locations over others.  The resulting market can cause more dense housing to be built on frequent bus lines than away from them.  The resulting developments may not be as dense or centrally organized as Portland's streetcar-stimulated Pearl District, but they form, in aggregate, a huge amount of the recent growth in inner city urban fabric, all over North America.

These images, for example, are from the Belmont Dairy redevelopment, along Portland's Belmont Street at 35th Avenue.  It includes a mix of apartments and townhouses, organised around a grocery store facing the street.  It's on the higher end of such redevelopments, much praised in the smart growth literature.  I know people who bought homes there, and they definitely cared that the Frequent Line 15 bus stopped right in front.  

(Line 15, by the way, is a motor bus, not a trolley bus.)

So why do these redevelopments along major bus lines not count as "buses stimulating development"?  "Stimulate," remember, doesn't mean "cause to occur all by itself."  It just means "help to occur, in conjunction with a lot of other favorable factors."  That's the only sense in which the Portland Streetcar stimulated the Pearl District, though we think about that case differently because the Streetcar and the neighborhood were designed together. 

Didn't the Line 15 bus stimulate the Belmont Dairy project in the same sense of the word?  Doesn't a bus line form part of the stimulus of any redevelopment built near its stops, except in cases where you're sure most residents won't care whether the bus is there?

It seems to me that to argue that "buses don't stimulate development," you'd have to argue that all those developments along frequent bus lines would have happened anyway, and sold for the same value to equally happy buyers, even if there were no frequent bus service -- which is to say, no frequent transit of any kind.

Does the development industry really believe that?   Do streetcar advocates even believe that?  Or is there a subtler meaning of "to stimulate" that is true of what streetcars do but not what bus lines clearly also do, perhaps to a lesser degree but over a much wider area?

Just asking.  I've read plenty of times that buses don't stimulate development, but I've never seen a data-based argument for that proposition.  If you have, please use the comments to point me to it.

Photos:  US EPA Smart Growth website

learning, again, from las vegas

Tired of arguing about streetcars?  Let's take a break and talk about something we're more likely to agree on -- Las Vegas! 

While the city plays a crucial role in American culture as a test-site for exotic street names, I suspect we'd mostly agree that it's not going to be a leader in sustainable urban form anytime soon. While the grid pattern of the city has some advantages (more on grids soon), Las Vegas has a particularly bad habit of building blocks of apartments in places where efficient transit will never be able to serve them, and where basic commercial needs are still too far to walk, thus achieving all of density's disadvantages and none of its benefits.

But there are surprises.  I just completed my annual trip to Las Vegas, to see family there, and thought I'd update this 2007 item from my personal blog about this capital of churn: