Brown Bag Discussion Series

Alain Bertaud

Maya Salwen Maya Salwen

Thank you to Alain Bertaud for leading this week’s brown bag discussion.

Public transportation is a key benefit of cities. In most cities, jobs are initially located near the city center and housing that is conveniently located near the public transportation that takes people to and from the center commands a premium. But as cities grow, their spatial structure often changes from monocentric to polycentric, with jobs and residences more dispersed. Over time people and businesses relocate to areas at a greater distance from the city center. 

In the New York City metropolitan area, about 74% of commuting trips take place between suburbs, as opposed to from the suburbs to the city center. This phenomenon is not unique to New York, it is seen in metropolitan areas worldwide—Paris and New York are virtually identical in this regard. However, public transportation systems are typically configured as a hub and spoke system, facilitating trips from suburbs to center. For example, the New York City subway is efficient for traveling in, out, and within Manhattan, but traveling from suburb to suburb within New Jersey is most efficient with a car.

Bertaud argues that, too often, urban planners identify their preferred mode of transit and then focus on including as many people as possible within its range. For him, this objective is backwards: the transit system should adapt to the structure of the city, not the other way around. Whatever the merits of subway lines, they are only viable for dense, compact cities, not for lower density, spread out systems. For example, both Barcelona and Atlanta have similar populations and roughly the same length of metro lines. In Barcelona, 30% of people take the metro to work, while in Atlanta it’s about 3%. To scale the Barcelona metro to Atlanta would require building about 3,500km of lines. Because it is a more compact city, Barcelona accommodates the same number of people with just 80km of line. In Atlanta, such a large capital investment per passenger would be unfeasible. There is also no turning back the clock on the spatial structure of Atlanta.

So what are the alternatives? Bertaud offers several recommendations and solutions.

  1. Transportation planners should focus on optimizing mobility instead of optimizing the chosen transportation system.
  2. Combine small individual vehicles with express mass transit that has stations about every 5km.
  3. Reduce the area used by moving individual vehicles by using “adaptive cruise control” and eventually fully autonomous vehicles. Both solutions would reduce the response time needed to stop a car increases a road’s capacity.
  4. Make parking entirely private to be paid for at market price

Currently many suburban residents choose to own a car in order to solve their transportation challenges. But cars take up a lot of space, and taxis are unaffordable for daily use. Car sharing presents an interesting possibility for reducing the land allocation for cars. New technology such as the folding car, which takes up less parking space, or Toyota’s i-Road Personal Mobility Vehicle, which is narrower and shorter than a traditional vehicle, are also promising. Integrating such vehicles into existing transportation systems will increase mobility between suburbs while ameliorating the land and labor costs that are currently associated with cars. 

You can find Alain Bertaud’s presentation here.

Tile image courtesy of Toyota UK.

Alain Bertaud

Alain Bertaud

Senior Research Scholar, NYU Stern Urbanization Project

alainbertaud.com

Alain Bertaud is a senior research scholar at the NYU Stern Urbanization Project. At the moment, he is writing a book about urban planning that is tentatively titled Order Without Design. Bertaud previously held the position of principal urban planner at the World Bank. After retiring from the Bank in 1999, he worked as an independent consultant. Prior to joining the World Bank he worked as a resident urban planner in a number of cities around the world: Bangkok, San Salvador (El Salvador), Port au Prince (Haiti), Sana’a (Yemen), New York, Paris, Tlemcen (Algeria), and Chandigarh (India).

Bertaud’s research, conducted in collaboration with his wife Marie-Agnès, aims to bridge the gap between operational urban planning and urban economics. Their work focuses primarily on the interaction between urban forms, real estate markets and regulations. Bertaud earned the Architecte DPLG diploma from the Ecole Nationale Supérieure des Beaux-Arts in Paris.

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