Associate Professor of Urban Planning and Transportation Policy
295 Lafayette Street
New York, NY 10012
Zhan Guo studies individuals’ travel behavior and explores innovative ways to influence that decision-making process to produce better social outcomes such as reduced congestion and carbon emissions. At the micro level, he focuses how travelers perceive travel alternatives and attributes and what discrepancies exist between perception and reality. The ability to reinforce, change, or even deceive that perception to promote the "right" behavior, and the methods used to do so, also figure largely in his research. At the macro level, he is interested in the effect of regulations, such as parking and street standards, mandatory affordable housing, and speed limit, on accessibility, equity, and safety, with a special focus on the (dis)connection between these regulations, market forces, and consumer preferences. Zhan has conducted empirical work in Boston, London, Washington DC, New York, San Francisco, Hong Kong, etc. His work has been covered by New York Times, Washington Post, Wall Street Journal, BBC, Economist, Le Monde, ABC Evening News, XInhua News Agency, People's Daily, the Atlantic Cities, Nudges.org, etc.
Zhan Guo received a B. Arch from Tianjin University, a MUD from Tsinghua University, China, and a MCP and a Ph.D in Urban Planning from MIT.
Mandatory inclusionary housing, which requires market-rate housing developments to include a proportion of affordable housing units, has the potential to deliver affordable housing in more affluent neighborhoods and create mixed-income communities. This study evaluates this potential effect in London, United Kingdom, where mandatory inclusionary housing has been implemented in all local authorities since the early 2000s. Comparing the spatial concentration and average neighborhood characteristics of affordable housing delivered under inclusionary housing and those created via conventional means (i.e., in the public or nonprofit sector), we find that a higher percentage of inclusionary affordable units are concentrated in a small number of neighborhoods, and both types of affordable units are more likely to be placed in disadvantaged neighborhoods than market-rate units are. We explore the ways in which local implementation of inclusionary housing could have allowed developers to shift some of the inclusionary affordable housing toward disadvantaged neighborhoods.
This research explores the recent practice of connecting on-site carsharing service with off-street parking standards in multifamily developments; the San Francisco Bay Area, California, is used as a case study. If implemented well, such a policy could help boost the carsharing industry and reduce off-street parking, which is often criticized as being oversupplied as a result of excessive off-street parking standards. In 2011, the authors surveyed all carsharing sites in the Bay Area and all new residential developments (completed after 2000) with on-site carsharing spaces. The results showed that a significant number of carsharing spaces were located on residential properties, but 70% of the spaces had been retrofitted into existing buildings. For the new developments, on-site carsharing did not result in a reduction in the amount of regular off-street parking. Interviews with 15 professionals from three stakeholder groups (planners, developers, and service providers) revealed that even though all the stakeholders were in favor of on-site carsharing at residential developments, three major barriers existed: a lack of incentives, the complexity of access design, and high transaction costs.
This paper examines the parking mandate in residential street standards in the U.S. Based on literature review and a national survey of 97 principal cities in the top 52 metro areas, it reveals two unjustified assumptions behind the mandate: traffic lanes must maintain the continuous alignment even with limited, slow traffic and parking demand must be satisfied with dedicated parking lanes in absence of price. The mandate is likely to force market to over-supply parking and under-supply housing. The paper calls for the removal of the parking mandate from street standards, and the deregulation of the residential street parking market.
This paper investigates the effect of home parking convenience on households' car usage, and the implications to residential parking policies. A random sample of 840 households is selected from a travel survey in the New York City region, and their home parking types are identified through Google Street View. It found that with the same car ownership level, households without off-street parking used cars much less, and relied more on alternative modes than those with off-street parking. For households with access to both garage and street parking, those who use the handy street parking tend to make more car tours than those who do not. In general, convenient home parking encourages households' car usage. Policy implications to the minimum off-street parking requirement, residents parking permit, street cleaning, and new urbanism neighborhood design are discussed.
This paper investigates the feasibility of charging residents for on-street parking in dense urban neighborhoods as a way to clear parking supply and demand. We elicited residents’ willingness to pay (WTP) for a hypothetical parking permit program in New York City using a payment card approach, and estimate the key determinants through a Double Hurdle model. A little more than half of respondents (52.5%) are willing to pay for an average $408 per year, even though the revenue is not specified to be return back to the neighborhoods. Pricing becomes more acceptable in neighborhoods where the major parking problem is shortage and crowding caused mainly by local residents instead of parking intrusion by non-residents. The WTP value varies by resident car ownership and home parking types. The results suggest that curb parking pricing for local residents might be both economically and politically feasible in certain dense urban neighborhoods.
Problem, research strategy, and findings: Local governments’ minimum street-width standards may force developers to oversupply, and residents to pay excessively for, on-street parking in residential neighborhoods. Such oversupply is often presumed to both encourage car ownership and reduce housing affordability, although little useful evidence exists either way. This article examines the impact of street-parking supply on the car ownership of households with off-street parking in the New York City area.
The off- and on-street parking supply for each household was measured through Google Street View and Bing Maps. The impact of on-street parking on car ownership levels was then estimated in an innovative multivariate model. The unique set-up of the case study ensures 1) the weak endogeneity between parking supply and car ownership and 2) the low correlation between off-street and on-street parking supply, two major methodological challenges of the study. Results show that free residential street parking increases private car ownership by nearly 9%; that is, the availability of free street parking explains 1 out of 11 cars owned by households with off-street parking.
Takeaway for practice: These results offer support for community street standards that make on-street parking supply optional. They also suggest the merits of leaving the decisions of whether, and how many, on-street parking spaces to provide in new residential developments to private markets rather than regulations.
Research support: This project was supported by grants from the University Transportation Research Center (Region 2) and the Wagner School Faculty Research Fund.
China faces rising rates of overweight, obesity, and physical inactivity among its citizens. Risk is highest in China’s rapidly growing cities and urban populations. Current urban development practices and policies in China heighten this risk. These include policies that support decentralization in land use planning; practices of neighborhood gating; and policies and practices tied to motor vehicle travel, transit planning, and bicycle and pedestrian infrastructure. In this paper, we review cultural, political, and economic issues that influence overweight, obesity, and inactivity in China. We examine key urban planning features and policies that shape urban environments that may compromise physical activity as part of everyday life, including walking and bicycling. We review the empirical research to identify planning and design strategies that support physical activity in other high-density cities in developing and developed countries. Finally, we identify successful strategies to increase physical activity in another growing, high-density city – New York City – to suggest strategies that may have relevance for rapidly urbanizing Chinese cities.
This research examines residential parking supply in London before and after the minimum off-street parking standard was replaced by a maximum one in 2004. Based on 11 428 residential developments after and 216 developments before the reform, it is found that parking supply was reduced by approximately 40 per cent. Ninety-eight per cent was caused by the removal of the minimum standard, while only 2 per cent was due the imposition of the maximum standard. However, the parking supply is actually higher in areas with the highest density and the best transit service than in the areas immediately outside; the adopted maximum standard follows a similar pattern. The market-oriented approach to parking regulation can reduce excessive parking, but it depends on the particular sub-markets. Complementary policies such as strict parking maxima, on-street parking controls and parking taxes are often necessary to form an efficient parking market.
This article explores the concept of “public commons” and its relationship with travel decisions under a unique setting: street cleaning in the New York City area. Using a natural experimental design, it investigates the impact of street cleaning on car usage for five hundred randomly selected households. Street cleaning encourages car usage for households without off-street parking and discourages car usage for households with off-street parking. The net effect is an increase of vehicle miles traveled by 7.1 percent, at least 27 percent of which is not a mere redistribution from non-street-cleaning days.
Congestion pricing and land use planning have been proposed as two promising strategies to reduce the externalities associated with driving, including traffic congestion, air pollution, and greenhouse gas emissions. However, they are often viewed by their proponents as substitutive instead of complementary to each other. Using data from a pilot mileage fee program run in Portland, OR, we explored whether congestion pricing and land use planning were mutually supportive in terms of vehicle miles traveled (VMT) reduction. We examined whether effective land use planning could reinforce the benefit of congestion pricing, and whether congestion pricing could strengthen the role of land use planning in encouraging travelers to reduce driving.
VMT data were collected over 10 months from 130 households, which were divided into two groups: those who paid a mileage charge with rates that varied by congestion level (i.e., congestion pricing) and those who paid a mileage charge with a flat structure. Using regression models to compare the two groups, we tested the effect of congestion pricing on VMT reduction across different land use patterns, and the effect of land use on VMT reduction with and without congestion pricing. With congestion pricing, the VMT reduction is greater in traditional (dense and mixed-use) neighborhoods than in suburban (single use, low-density) neighborhoods, probably because of the availability of travel alternatives in the former. Under the same land use pattern, land use attributes explain more variance of household VMT when congestion pricing is implemented, suggesting that this form of mileage fee could make land use planning a more effective mechanism to reduce VMT. In summary, land use planning and congestion pricing appear to be mutually supportive.
For policymakers considering mileage pricing, land use planning affects not only the economic viability but also the political feasibility of a pricing scheme. For urban planners, congestion pricing provides both opportunities and challenges to crafting land use policies that will reduce VMT. For example, a pricing zone that overlaps with dense, mixed-use and transit-accessible development, can reinforce the benefits of these development patterns and encourage greater behavioral changes.
This paper investigates the impact of schematic transit maps on passengers' travel decisions. It does two things: First, it proposes an analysis framework that defines four types of information delivered from a transit map: distortion, restoration, codification, and cognition. It then considers the potential impact of this information on three types of travel decisions: location, mode, and path choices.1 Second, it conducts an empirical analysis to explore the impact of the famous London tube map on passengers' path choice in the London Underground (LUL). Using data collected by LUL from 1998 to 2005, the paper develops a path choice model and compares the influence between the distorted tube map (map distance) and reality (travel time) on passengers' path choice behavior. Results show that the elasticity of the map distance is twice that of the travel time, which suggests that passengers often trust the tube map more than their own travel experience on deciding the ‘‘best'' travel path. This is true even for the most experienced passengers using the system. The codification of transfer connections on the tube map, either as a simple dot or as an extended link, could affect passengers' transfer decisions. The implications to transit operation and planning, such as trip assignments, overcrowding mitigation, and the deployment of Advanced Transit Information System (ATIS), are also discussed.
Few studies have adequately assessed the cost of transfers in public transport systems, or provided useful guidance on transfer improvements, such as where to invest (which facility), how to invest (which aspect), and how much to invest (quantitative justification of the investment). This paper proposes a new method based on path choice,3 taking into account both the operator's service supply and the customers' subjective perceptions to assess transfer cost and to identify ways to reduce it. This method evaluates different transfer components (e.g., transfer walking, waiting, and penalty) with distinct policy solutions and differentiates between transfer stations and movements.
The method is applied to one of the largest and most complex public transport systems in the world, the London Underground (LUL), with a focus on 17 major transfer stations and 303 transfer movements. This study confirms that transfers pose a significant cost to LUL, and that cost is distributed unevenly across stations and across platforms at a station.
Transfer stations are perceived very differently by passengers in terms of their overall cost and composition. The case study suggests that a better understanding of transfer behavior and improvements to the transfer experience could significantly benefit public transport systems.
This paper investigates the causal effect of pedestrian environments on walking behavior and focuses on the issue of research design. The paper differentiates between two types of research designs:treatment-based and traveler-based. The first approach emphasizes the variation of the treatment (pedestrian environments), and generally compares distinct neighborhoods, such as urban vs. suburban or transit-oriented vs. auto-dependent. The second approach emphasizes the homogeneity of subject (pedestrians), and aims at the same pedestrian under different environments normally due to home relocation, or the improvement of pedestrian environments.
This paper presents a third method, following a traveler-based research design while providing the pedestrian multiple walking paths with different pedestrian environments.
There is a lack of consensus as to whether the relationship between the built environment and travel is causal and, if it is, the extent of this causality. This problem is largely caused by inappropriate research designs adopted in many studies. This paper proposes a new method (based on path choice) to investigate the causal effect of the pedestrian environment on the utility of walking. Specifically, the paper examines how the pedestrian environment affects subway commuters' egress path choice from a station to their workplaces in downtown Boston. The path-based measure is sensitive enough to capture minor differences in the environment experienced by pedestrians. More importantly, path
choice is less likely to correlate with job and housing location choices, and therefore largely avoids the self-selection problem. The results suggest that the pedestrian environment can significantly affect a person's walking experience and the utility of walking along a path.
This paper investigates the impact of pedestrian environments on walking behavior, and the related choice of travel path for transit riders. Activity logs from trip surveys combined with transit-route and land-use information are used to fit discrete-choice models of how riders choose among multiple paths to downtown destinations. The work illustrates (1) how the quality of pedestrian environments along transit egress paths affects transfers inside a transit system, and (2) how the impedance of transferring affects egress walking path choices. The use of GIS techniques for path-based spatial analysis is key to understanding the impact of pedestrian environments on walking behavior at the street level. The results show that desirable pedestrian environments encourage transit riders to choose paths that are ‘friendlier', even if they involve more walking after leaving transit. Policy implications for land-use planning and transit service planning are discussed.
Yellow-dust storms (YDSs) have attracted increasing attention worldwide in the past decade. They can extensively disrupt socioeconomic activities and pose hazards to ecosystems, as well as human health. In recent years, China has invested multi-billions of dollars to mitigate the impact of YDSs. However, the effectiveness of such YDS-control programs has rarely been evaluated. This research develops a causal model to quantify the environmental benefits of YDS-control programs in China, and further employs regional economic models to evaluate the ensuing economic impacts. The economic benefits generated from the YDS-control programs have remained stable across the years, primarily because of the multiplier effect of the investments, while the environmental benefits tend to decline over time. Our results suggest that YDS-control programs should consider stimulating local economic activities in addition to environmental goals in order to be cost-effective and sustainable in the long term.
This paper explores the weather-ridership relationship and its potential applications in transit operations and planning. Using the Chicago Transit Authority (CTA) as a case, the paper investigates the impact of five weather elements (temperature, rain, snow, wind, and fog) on daily bus and rail ridership, and its variation across modes, day types, and seasons. The resulting relationships are applied to the CTA ridership trend analysis, showing how preliminary findings may change after controlling for weather. The paper emphasizes the importance of having a theoretical framework encompassing weather and travel.
Transfers can have an important influence on customer satisfaction and on whether many customers find transit service an attractive option. An empirical investigation of transfers from commuter rail to subway in downtown Boston, Massachusetts, is conducted. The research identifies a higher transfer penalty between commuter rail and subway than between subway lines. Fare payment and network familiarity also are shown to affect transfer decisions. Despite a large variation of the transfer experience between the stations analyzed, riders seem to have a similar perception of transfers. For example, in most cases, the perceived transfer penalty has a narrow distribution, with a coefficient of variation below 0.5. Potential applications of the research findings to transit planning are presented.
Transit riders negatively perceive transfers because of their inconvenience, often referred to as a transfer penalty. Understanding what affects the transfer penalty can have significant implications for a transit authority and also lead to potential improvements in ridership forecasting models. A new method was developed to assess the transfer penalty on the basis of onboard survey data, a partial path choice model, and geographic information system techniques. This approach was applied to the Massachusetts Bay Transportation Authority (MBTA)subway system in downtown Boston. The new method improves the estimates of the transfer penalty, reduces the complexity of data processing, and improves the overall understanding of the perception of transfers.