HCP Q&A: Faan Chen on "Driving and the Built Environment"

April 16, 2020

HCP Q&A: Dr. Faan Chen, Postdoctoral Fellow

"Driving and the Built Environment:  Is Transit-Oriented Development (TOD) Effective in Shanghai?"

The rapid growth of Chinese cities, including Shanghai, has presented many challenges for local government officials, planning and transit practitioners, and property developers. These challenges include traffic congestion, energy consumption, and emissions of both air pollutants and carbon dioxide (CO2), the leading greenhouse gas contributing to climate change. As one of the more visible urban forms of smart growth, Transit-Oriented Development (TOD) has been actively promoted as a model for urban development to respond to these challenges.  The Harvard-China Project caught up with Faan Chen, one of its postdoctoral fellows, to learn more about a recent study he has led on the subject that is currently being peer-reviewed by a journal. 

Previous empirical studies of TOD have provided insights into the associations between travel behavior and built environment designed to encourage transit use. However, the vast majority of studies have been conducted in North American and European cities. Such research is still in its infancy in most developing countries, including China, where residential and transport choices are likely to be more constrained, and travel-related attitudes quite different from those in the developed world. Using data collected from more than 8,000 Shanghai residents living in both TOD and non-TOD neighborhoods, the study by Chen and colleagues aims to help fill the gaps by investigating the causal relationship between the built environment of TOD and travel behavior. By exploring these issues for residents of different housing types in China, the team is able to control for residential self-selection, i.e., the fact that some are drawn to TOD areas because they already favor transit, with travel behavior that reflects this preexisting attitude more than the effect of TOD built environment itself. Specifically, the research team examines whether – and to what extent – altering the built environment can actually lead to meaningful changes in travel behavior, e.g., less Vehicle Kilometers Traveled (VKT) and less associated CO2 and air pollution emissions.

Harvard-China Project We understand that TOD exists in 48 places in the U.S. on state, regional and local scales. Has TOD become a priority in many of China’s major cities, or are you seeing it only in Shanghai? Are officials at a national level pushing TOD, or is it spearheaded by local entities?
Faan Chen:  Since Peter Calthorpe introduced TOD in his book, The Next American Metropolis in 1993, it has been actively promoted as a model for urban development. It has also been increasingly advocated as an effective response to urban growth challenges, including traffic congestion, energy consumption and greenhouse gas and pollution emissions. This is especially true in developing countries like China, where rapid urbanization is occurring. China’s urban growth rate is 2-4% per year, and the urban share of the population has grown rapidly in just 20 years, from less than 30% in 1997 to more than 60% in 2019. TOD has become a priority in many of China’s major cities as urban rail transit systems are constructed. This is the case in Shanghai, which has the world’s largest rail transit system by total route length (420 miles). 

In recent years, governments and planning organizations have vigorously developed and promoted national-level legal standards and policies supportive of TOD. These include the “National New-type Urbanization Plan (2014-2020),” published by the State Council; “Planning Guidance for TOD,” developed by the Ministry of Housing and Urban-Rural Development in 2015; and more. In addition, TOD policies and guidelines have been developed by local governments and entities in cities besides Shanghai, such as Shenzhen, Guangzhou, and Chengdu.

HCP To collect data, you and colleagues completed two years of interviews with more than 8,000 residents of TOD and non-TOD neighborhoods. What was the biggest take-away from this survey, in terms of their motivation to either reside or not reside near transit-oriented development?
FC:  For me, it was quite interesting to talk with residents face-to-face. I, of course, could not speak directly with all respondents, but tried to communicate with as many as possible and quite enjoyed that experience. You can learn about their thinking, their relocation history, their life events, and even their future life plans. Our questionnaire explores a variety of topics, including individual and household socio-demographics, travel behavior records, residential preferences, travel-related attitudes, and so forth.  This data can support research on many related topics, including travel behavior, housing mobility, social inequality, and others.

In terms of motivation for residential relocation, we find there are three important factors that draw people to TODs: 1) easy access to the public transport system; 2) easy access to highways; and 3) easy access to facilities, shops and services for daily life. On the other hand, there are three key criteria that people consider when looking for housing in non-TODs: 1) cost of housing; 2) quality of neighborhood; and 3) easy access to highways. Based on these results, we anticipate a possible future publication entitled “Where people want to be: An empirical analysis from Shanghai.”

HCP:  Likewise, what were some individual characteristics that you saw in those who choose to live in a TOD area? For example, did education, income, or commuting distance have a significant effect?
FC:  It’s interesting to find that at the individual level, residents in TOD areas tend to be younger, with higher educational levels, and more often working in government positions than those in non-TOD areas. At the household level, people living in TOD areas tend to have smaller households, fewer minors, less ownership of cars, and higher incomes.  It is evident that in terms of choosing where we live, our socio-demographics and travel attitudes do have great impacts on residential relocation choices.

HCP What is one behavior or circumstance in China that allows TOD to flourish, as opposed to the United States?
FC:  Conceptually, rail transit is of course the main physical attribute that makes TOD work.  The Ministry of Transport of China initiated the Transit Metropolis Programme in 2011, through which 37 cities were selected to serve as pilots for TOD initiatives with rail transit expansions. To date, there are 45 cities with urban rail transit systems (operational or under construction) in mainland China. This creates a strong environment for TOD to flourish. When comparing this to the US, you find a different picture because development is still so auto-dependent. But to be honest, a considerable number of the so-called TODs in both China and the US should also more appropriately be considered TAD (Transit-Adjacent Development) or TRD (Transit-Related Development), underdeveloped versions that may feature TOD physical forms and project configurations but without the full functional outcomes. From this point of view, I think one of the challenges that China and the US should address will be moving TOD more fully from rhetoric to reality.

HCP TOD can have an impact on emissions. Can you speak about this, and other likely positive impacts of residing in a TOD neighborhood?
FC:  Well, as you know, the transportation sector is one of the largest contributors to CO2 emissions. Globally, according to the International Energy Agency, transport accounts for 24% of energy-related CO2 emissions; the share is much lower, but growing, in China. Previous empirical studies have shown that residents living in TOD neighborhoods tend to have less VKT than their counterparts in non-TOD neighborhoods, and therefore lower energy consumption and emissions. More specifically, from the results of our research, a randomly selected resident’s personal daily VKT will decrease by an average of 38% when he/she moves from a non-TOD neighborhood to a TOD one, chiefly due to the impact of the built environment of TOD.  At an aggregate level, this means huge energy-saving and emission reductions. I emphasize the greenhouse gas CO2 here, but TOD of course has a similar effect on air pollution emissions.

Other benefits for new and existing residents living in TODs are increased transit ridership, increased walking and healthier lifestyles, reduction in dependency on cars, and increased efficiency in land use.

HCP How do you see this research informing policy-makers as they consider construction of more TOD neighborhoods? And what are the next steps for this research?
FC:  Overall, this study sheds substantial new light on the spatial heterogeneity of linkages between the built environment of TOD and travel behavior in the context of different housing types in China, controlling for residential self-selection that critics may otherwise suggest explain the behavioral differences. This provides policymakers with further assurance that land-use and transport policies aiming to change the built environment could indeed stimulate meaningful changes in travel behavior. In other words, TOD works!  However, the full impact of the TOD built environment varies dramatically by different housing types. Policies toward land use and transport should respond to the different characteristics of residential self-selection among different types of housing. Moreover, the nature and magnitude of the impacts of the built environment on travel behavior could be used to build a user-friendly spreadsheet-based analytical tool that could provide a sound basis for urban planners, transit practitioners and developers to better evaluate future regional development and transportation scenarios, with the aim of shifting more travel to public transit.

From the structural survey interviews, we learn that different types of housing in the Chinese context are connected to different social-psychological environments. In particular, the natures of public housing and replacement housing (that offered by governments to residents displaced by development) are quite distinct from other types of housing, and the population structure and attitudes towards government services of people in those housing categories also differ. These factors might have great impacts on activity-travel patterns. We next plan to investigate the connection between social-psychological characteristics and activity-travel behavior, in the context of different housing types. Findings from such a study would have potentially tremendous benefits for practical policymaking regarding urban and transport planning and governance.

Reference: Faan Chen, Jiaorong Wu, Xiaohong Chen, Chris P. Nielsen. Submitted (2020). “Disentangling the impacts of the built environment and self-selection on travel behavior: An empirical study in the context of different housing types.”