Enrique Penelosa on Transportation and Justice

While I can't agree with everything he says (the necessity for government land use planning creeps me out), most of the things this article talks about make my heart soar.

https://www.theguardian.com/cities/2016/oct/17/enrique-penalosa-mayor-bogota-colombia-bus-traffic-un-habitat

A few quotes:

"way we build cities is much more important for the future happiness of people than economic development. For example, if we are able to save a couple of hectares of land for a public park, it can make people happier for thousands of years to come."

What is the value of dedicated ROW for a BRT? It's hard to calculate something that will be providing benefits a hundred years into the future. 

"Cities that move by bicycle and public transport are more democratic, more egalitarian. In a “developing country”, a protected bikeway is not just a way of keeping the cyclist safe; it is a symbol that shows that a citizen riding a $50 bicycle is equally important to one driving a $50,000 car"

If only NYC could get the message.

"Mobility is a very peculiar challenge for a city – different from health or education – because it’s one problem that tends to get worse as societies get richer.

It's always nice when someone recognizes that maximizing mobility is a flawed paradigm for cities.

"We must understand that an advanced city is not one where poor residents use cars, but one where rich residents use public transport. "

I think this idea drove the 'Streetcar Renaissance' a decade back. Transit planners recognizing that if transit is continue to exist as the poor suburbanize and the less-poor buy cars, transit has to be able to attract choice riders--relying on the transit dependent living/working in central cities is no longer a viable strategy. Streetcars were supposed to be the clean, quiet, comfortable transit that affluent people would accept. Sadly, too many streetcars forgot that 'frequent' and 'reliable' are virtues of effective transit EVERYONE appreciates, and too many streetcars wound lacking dedicated ROW, an stuck in traffic.

"If all citizens are equal, then somebody who is walking or on a bike has a right to the same amount of road space as somebody in a Rolls-Royce or luxury car. And a bus with 150 passengers has a right to 150 times more road space than a car with one passenger. Which means we should give exclusive lanes to buses and create Bus Rapid Transit (BRT) systems; it’s the only solution" 

 He has my vote. Admittedly, most buses in America don't carry 150 people. But in Latin America, the 'Overground' of triple articulated BRT's carry loads to rival subway systems. Elsewhere, I've blogged about what it takes for a BRT to do better than autos, in terms of lane usage: 90 persons per bus, 12 minute frequency.

"The whole challenge of urban mobility is not an engineering challenge but a political one. Today, it’s almost as unjust and absurd to see a bus in a traffic jam as it was, a century or so ago, not to allow women to vote"

Does make you think. What justification does this disproportionate burden occur on? That car owners are wealthier and more likely to vote?

"when shopping malls replace public space as a meeting place for people, it’s a symptom that the city is ill"

An interesting contention. Agreed that privatized space can never replace public space, because it can never provide a truly public realm. As a private realm, members of the public can be excluded. And when part of the public is barred from the 'forum', it becomes a question how well the population of the forum actually represents the 'public'. Always important to think about the alternative--and the alternative to democracy is riots and assassinations.

Urban Phase Shift?

One of the comments on this article was so great I had to repost it:

When I took my Urban Economics course from Barton Smith, one of the observations Smith told us in class was that whenever prices for major goods and services in an urbanized area keep going up (and housing is certainly a big part of most people's budgets), eventually prices will reach a point where they will become a market signal to everyone that the urbanized area needs to stop growing. Population growth will either come to a halt, or people will start leaving until prices fall to an equilibrium where people can afford to live there again. - Neil Meyer 

I think it gets to the core of why city promoters like transportation improvements--without affordable housing, cities can't grow. Affordable housing includes both rents and access costs. As rents in one area rise, people can offset that by moving to nearby areas with lower rents (and higher access costs).
In pre-industrial (and third world slums) the only access available is by walking, and so some truly hideous densities result.

It's theoretically feasible that a city might stop growing***. But most cities don't--instead, they invest in transportation improvements. NYC built it's first subways in the name of "De-Congestion".

One of the ideas I'm kicking round is an urban scaling induced 'phase shift' in the effectiveness of transportation improvements. Namely, total metro population drives average metropolitan density. (As you get bigger, you naturally get denser). At small sizes and low densities, auto-mobility works: Land is cheap, parking is available, walking anywhere is madness. And it keeps working, as long as your addition of automobile capacity keeps up with congestion.

However, while travel is an 'derived demand' in terms of the number of trips made, it's a 'induced demand' in terms of the length of trips made. If you make traveling cheap and easy, people go further.* Urban form is 'set' by the dominant transportation mode at the time of construction**. So places developed under conditions of auto-mobility tend to be low-density with segregated land-uses. The large amount of travel required to get around for basic needs is 'baked-in' at that point.

This is problematic, if the metropolitan area keeps expanding.

from: https://people.hofstra.edu/geotrans/eng/ch6en/conc6en/cellular_automata.html

As the number of zones increases, the average distance from one zone to another also increases. Which means, all else equal, the amount of travel required to get to all the places you want to go also rises. Simply because things are scattered about: home in one place, work in another, groceries in a third, kids-school in a fourth, soccer in another, ballet-practice in another, dentist in yet another.

The big problem is that the increase in average distance between all of these things is non-linear. Every additional 'zone' you add to a city, the average distance rises more than it did for the last zone.
Even if the road lane miles per capita (and associated costs) remain constant, the amount of travel doesn't. As travel demand outstrips supply, congestion results.

Some cities try to fix this increasing congestion with massive increases in road-building. Failure is inevitable. Exponential increases in travel require exponential increases in road capacity, imposing exponential costs on a linearly growing population.

And so at some point, every city gets the 'rapid transit bug'. And it has to be rapid transit, because only rapid transit makes it possible to avoid congestion. Non-rapid transit, such as regular buses and streetcars, are undeniably cheaper to build than rapid transit (sometimes by an order of magnitude).

But that doesn't matter. Rapid transit is premium transit*****. It's transit for choice riders (people who could drive, but choose not to). And to get people to make that choice, it has to be better (in some way) that the driving alternative.

Non-rapid transit suffers from congestion. It's less convenient, less reliable, and less comfortable than  your personal automobile. You don't have a 'locker' to store things in, and hauling groceries is difficult. Thus, it can almost never compete with a private automobile (excepting when parking costs/hassles are enormous).****

Rapid transit is better than the personal automobile when it is a) faster, b) cheaper, and c) more reliable. 'a' only happens when congestion is fierce; transit vehicles make repeated stops. 'b' seems simple, but for most people a car is a 'stock' of mobility they can draw upon even with no money, while transit is a 'pay-per-use' thing, so it seems expensive, even if it is less expensive in aggregate. Again, 'c' is reliant on congestion to work.

In summary: Auto-mobility works until it doesn't. It stops working because average travel distances increase exponentially as the metro area expands, while population increases linearly. This makes it impossible to keep expanding roadway capacity to match demand. (Some try; all fail). As travel demand outstrips supply, congestion results.

The total amount of delay drivers experience is exponentially proportional to the amount of congestion (from: https://ops.fhwa.dot.gov/congestion_report/chapter2.htm) The AADT/C ratio is the ratio of traffic to capacity.

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***This may be one of the reasons for competing cities, closer together. When a city reaches maximum walkable density, it makes a great deal of sense to go elsewhere. Of course, large cities have huge advantages in terms of access to resources and agglomeration economies, which (typically) more than offset the cost of congestion. I expect the only time you'd really see such a switch is for 'Twin cities' like Minneapolis-St. Paul, or the Texas MetroPlex.

*The reverse is also true. As congestion increases, trip length should start falling.

**The trouble being that urban form is fixed at date of construction, and is very difficult to retrofit for alternative transportation modes. Adding highways to NYC came at enormous financial and social cots. Retrofitting auto-dependent cities will likely be painful/costly as well.

****Which is why buses to downtowns, Universities and hospitals work--they are all places with terrible parking.

*****The political quid-pro-quo of rapid transit for dependent riders is that "Hey, you too can ride the premium transit!". The flip side to that is that the high cost of rapid transit means less of it is provided--its goes fewer places. Typically, bus operations get cut to pay for capital improvements, which leaves the transit-dependent population worse off.