Zhang, Lei; Hong, Jinhyun; Nasri, Arefeh; Shen, Qing. (2012). How Built Environment Affects Travel Behavior: A Comparative Analysis of the Connections between Land Use and Vehicle Miles Traveled in US Cities. Journal of Transport and Land Use, 5(3).
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Abstract
Mixed findings have been reported in previous research regarding the impact of built environment on travel behavior, i.e. statistically and practically significant effects found in a number of empirical studies and insignificant correlations shown in many other studies. It is not clear why the estimated impact is stronger or weaker in certain urban areas, and how effective a proposed land use change/policy will be in changing certain travel behavior. This knowledge gap has made it difficult for decision makers to evaluate land use plans and policies according to their impact on vehicle miles traveled (VMT), and consequently their impact on congestion mitigation, energy conservation, and pollution and green house gas emission reduction. This research has several objectives: (1) Re-examine the effects of built-environment factors on travel behavior, in particular VMT in five U.S. metropolitan areas grouped into four case study areas; (2) Develop consistent models in all case study areas with the same model specification and datasets to enable direct comparisons; (3) Identify factors such as existing land use characteristics and land use policy decision-making processes that may explain the different impacts of built environment on VMT in different urban areas; and (4) Provide a prototype tool for government agencies and decision-makers to estimate the impact of proposed land use changes on VMT. The four case study areas include Seattle, WA; Richmond-Petersburg and Norfolk-Virginia Beach, VA; Baltimore, MD; and Washington DC. Our empirical analysis employs Bayesian multilevel models with various person-level socio-economic and demographic variables and five built-environment factors including residential density, employment density, entropy (measuring level of mixed-use development), average block size (measuring transit/walking friendliness), and distance to city center (measuring decentralization and level of infill development). Our findings show that promoting compact, mixed-use, small-block and infill developments can be effective in reducing VMT per person in all four case study areas. However, the effectiveness of land use plans and policies encouraging these types of land developments is different both across case study areas and within the same case study area. We have identified several factors that potentially influence the connection between built environment shifts and VMT changes including urban area size, existing built environment characteristics, transit service coverage and quality, and land use decision-making processes.
Keywords
Built environment; Land use change; Travel behavior; Vehicle miles traveled (VMT); Multilevel Bayesian model; U.S. urban transportation planning policy
Pan, H., Shen, Q., & Zhao, T. (2013). Travel and Car Ownership of Residents near New Suburban Metro Stations in Shanghai, China. Transportation Research Record, 2394(1), 63–69.
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Abstract
Large cities in China are building extensive rail transit systems in combination with transit-oriented development in suburban areas, so that public transportation can play a leading role in supporting rapid urban expansion. Shanghai, China has been a leader in this planning approach. Shanghai's experience can be valuable for other cities facing similar pressures of urbanization, suburbanization, and motorization while striving to improve livability and reduce greenhouse gas emissions. To gain useful insights from Shanghai, a travel survey of residents in a recently developed suburban metro station area was conducted to examine how the city's mass rapid transit (MRT) has influenced residents’ travel and car ownership. With statistical methods, including logistic regression, it was found that (a) MRT was generally adequate in supporting the station area's economic relationships with the central city and local employment locations; (b) a high percentage of residents intended to commute by the MRT when they moved to the suburban station area, and their original intention positively influenced their current travel and car ownership; and (c) rail transit may help temporarily reduce the pace of motorization in households near suburban metro stations by delaying a car purchase and lowering the probability of car use in commuting. However, it was also found that car ownership had been increasing quite rapidly despite the positive effects of a much expanded and improved metro system, and that once a person owned a car, he or she would most likely drive to work.
Levine, J., Grengs, J., Shen, Q., & Shen, Q. (2012). Does Accessibility Require Density or Speed?. Journal of the American Planning Association, 78(2), 157–172.
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Abstract
Problem, research strategy, and findings: Advocates of accessibility as a transportation performance metric often assert that it requires higher density. Conversely, traditional transportation planning methods have valued speed per se as an indicator of success in transportation. In examining these claims, we make two methodological innovations. The first is a new intermetropolitan gravity-based accessibility metric. Second, we decompose the impact of density on accessibility to highlight the distinct opposing influences of speed and proximity in a manner that illustrates different families of relationships between these two factors. This reveals that denser metropolitan regions have slower travel speeds but greater origin-destination proximity. The former effect tends to degrade accessibility while the latter tends to enhance it. Despite theoretical reasons to expect that the speed effect dominates, results suggest that the proximity effect dominates, rendering the denser metropolitan areas more accessible.
Takeaway for practice: Having destinations nearby, as when densities are high, offers benefits even when the associated congestion slows traffic. Where land use policy frequently seeks to support low-development densities in part in an attempt to maintain travel speeds and forestall traffic congestion, our findings suggest that compact development can often improve transportation outcomes.
Research support: Environmental Protection Agency project RD-83334901-0, FHWA Cooperative Agreement Number: DTFH61-07-H-00037, and the Graham Environmental Sustainability Institute at the University of Michigan.
Keywords
accessibility; mobility; speed; proximity; transportation planning
Pan, H., Shen, Q., & Liu, C. (2011).. Transit-Oriented Development at the Urban Periphery: Insights from a Case Study in Shanghai, China. Transportation Research Record: Journal of the Transportation Research Board, 2245(1), 95–102.
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Abstract
Major cities in China are extending rail transit into the urban periphery to counter urban growth and suburbanization that are automobile-driven and automobile-dependent. In the meantime, transit-oriented development (TOD) has been adopted widely in Chinese cities. Given the adoption of the TOD concept by many rail transit station areas at the peripheries of metropolitan regions, it is imperative to explore how TOD can be applied appropriately there. In this study, two station areas were examined in Songjiang, a district located approximately 30 km from the city center of Shanghai, China. These station areas have developed according to some basic TOD principles, and, in many important ways, they are representative of newly developed rail transit station areas in Shanghai and in other major Chinese cities. The conduct of a questionnaire survey allowed for investigation of resident travel behavior, assessment of the effectiveness of the TOD application, and discussion of how TOD should be adapted to peripheral locations in a large and complex metropolitan region. The study concluded that planners must carefully substantiate the basic TOD concept in connection with this particular kind of application setting. Careful consideration should be paid to mixed land use, differentiated density, and to pedestrian and bicycle travel and their connection with rail transit. Planners also must pay close attention to each peripheral area's economic and social conditions, as well as its relationships with the central city and with other parts of the metropolitan region. This case study not only provided timely feedback on current planning practice in Shanghai and other Chinese cities but also contributed to the literature on the adaptation of TOD to local circumstances.
The Mobility Innovation Center announced that Qing Shen, professor of Urban Design & Planning and an expert in transportation planning and policy, has received a $100,000 award to study commuting patterns and develop a model to understand the effect of telework and flexible scheduling. The project will build off the existing Commute Trip Reduction (CTR) survey for employers who are in the CTR program as required by state law in the central city portion of Seattle. In addition, a complementary…
Yang, Jiawen; Shen, Qing; Shen, Jinzhen; He, Canfei. (2012). Transport Impacts of Clustered Development in Beijing: Compact Development Versus Overconcentration. Urban Studies, 49(6), 1315 – 1331.
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Abstract
This research aims to inform the compact city discussion with a case study of Beijing, where urban planning has emphasised clustered suburban development in the past half-century. It uses three decades of census data to describe Beijing's spatial development trajectory and a household survey to assess its transport impacts. The research reveals an overconcentration of urban activities as a result of the featureless expansion of the central built-up area and the absorption of the suburban clusters; and, a lengthened commuting time stemming from the observed spatial development pattern. Beijing's experience adds to the existing literature by informing the search for good city forms in urban areas of high density. It is essential to differentiate compact development from overconcentration when combating sprawling development. Developing and maintaining suburban nodal characteristics around public transit can reduce travel in high-density urban areas.
Keywords
Jobs-housing Balance; Commuting Patterns; Urban; Growth; City; Towns
Shen, Qing; Wang, Yiyuan; Gifford, Casey. (2021). Exploring Partnership Between Transit Agency And Shared Mobility Company: An Incentive Program For App-based Carpooling. Transportation, 48(5), 2585 – 2603.
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Abstract
How should public transit agencies deliver mobility services in the era of shared mobility? Previous literature recommends that transit agencies actively build partnerships with mobility service companies from the private sector, yet public transit agencies are still in search of a solid empirical basis to help envision the consequences of doing so. This paper presents an effort to fill this gap by studying a recent experiment of shared mobility public-private partnership, the carpool incentive fund program launched by King County Metro in the Seattle region. This program offers monetary incentives for participants who commute using a dynamic app-based carpooling service. Through descriptive analysis and a series of logistic regression models, we find that the monetary incentive to encourage the use of app-based carpooling generates some promising outcomes while having distinctive limitations. In particular, it facilitates the growth of carpooling by making carpooling a competitive commuting option for long-distance commuters. Moreover, our evidence suggests that the newly generated carpooling trips mostly substitute single-occupancy vehicles, thus contributing to a reduction of regional VMT. The empirical results of this research will not only help King County Metro devise its future policies but also highlight an appealing alternative for other transit agencies in designing an integrated urban transportation system in the era of shared mobility.
Keywords
Shared Mobility; Public-Private Partnership; App-based Carpooling; Incentive Fund; Transit Agencies; Incentives; Commuting; Public Transportation; Mobility; Regression Analysis; Regression Models; Partnerships; Vehicles; Car Pools; Private Sector; Occupancy; Transportation Systems; Mass Transit; Transportation Planning; Empirical Analysis; Urban Transportation
Hong, Jinhyun; Shen, Qing. (2013). Residential Density and Transportation Emissions: Examining the Connection by Addressing Spatial Autocorrelation and Self-Selection. Transportation Research Part D-transport And Environment, 22, 75 – 79.
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Abstract
This paper examines the effect of residential density on CO2 equivalent from automobile using more specific emission factors based on vehicle and trip characteristics, and by addressing problems of spatial autocorrelation and self-selection. Drawing on the 2006 Puget Sound Regional Council Household Activity Survey data, the 2005 parcel and building database, the 2000 US Census data, and emission factors estimated using the Motor Vehicle Emission Simulator, we analyze the influence of residential density on road-based transportation emissions. In addition, a Bayesian multilevel model with spatial random effects and instrumental variables is employed to control for spatial autocorrelation and self-selection. The results indicate that the effect of residential density on transportation emissions is influenced by spatial correlation and self-selection. Our results still show, however, that increasing residential density leads to a significant reduction in transportation emissions. (C) 2013 Elsevier Ltd. All rights reserved.
Keywords
Urban Form; Travel; Transportation Emissions; Residential Density; Confounding By Location; Self-selection
Wang, Yiyuan; Shen, Qing; Abu Ashour, Lamis; Dannenberg, Andrew L. (2022). Ensuring Equitable Transportation For The Disadvantaged: Paratransit Usage By Persons With Disabilities During The Covid-19 Pandemic. Transportation Research Part A: Policy & Practice, 159, 84 – 95.
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Abstract
Paratransit services developed under the Americans with Disabilities Act are a critical transportation means for persons with disabilities to meet their basic needs, but the COVID-19 pandemic posed an unprecedented challenge to service providers. To safeguard transportation equity, this study used complete records of service trips and riders obtained from the Access Transportation Program in the Seattle region for an empirical analysis aimed at answering two research questions. First, how did the ridership and trip purposes of paratransit change after the outbreak of COVID-19? Second, what factors explained the users' changing levels of service usage in response to the pandemic? Statistical methods, including a Hurdle model, were employed as the analytical tools. The results show that paratransit ridership dramatically decreased during 2020 with the most substantial reductions of working and non-essential personal trips, and that most of the remaining trips were for medical purposes. The results also indicate that riders' service usage during the pandemic was associated with their sociodemographic characteristics, disability conditions, and pre-pandemic travel demand. When controlling for other factors, riders who lived in neighborhoods with lower income and lower access to personal vehicles were more dependent on the service. Based on the empirical findings, we recommend that when developing plans for future disruptive events, public transit agencies should promptly implement safety measures, identify and prioritize neighborhoods that are most in need of mobility services, and actively pursue collaboration with other organizations for innovative service delivery options.
Keywords
Covid-19 Pandemic; Public Transit; People With Disabilities; Americans With Disabilities Act Of 1990; Public Transit Ridership; Paratransit Services; Seattle (wash.); Americans With Disabilities Act (ada); Hurdle Model; Paratransit; Transportation Equity; Mobility; Justice
Zhao, Zhan; Zhao, Jinhua; Shen, Qing. (2013). Has Transportation Demand of Shanghai, China, Passed Its Peak Growth? Transportation Research Record, 2394, 85 – 92.
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Abstract
On the basis of four comprehensive transportation surveys in Shanghai, China, this study examined the latest trends in Shanghai's travel demand; investigated their social, economic, and spatial drivers; and compared the pace of travel demand growth in three periods: 1980s to early 1990s, early 1990s to mid-2000s, and mid-2000s to the present. The demand growth was relatively slow in the first period and then sped up in the second before it returned to a slower pace in the third period. As for trip purpose, Shanghai's travel is much more diversified than previously, with an increasing share of noncommuting trips (from 28% in 1995 to 46% in 2009). Spatially, travel demand is dispersed from the central district to peripheral districts because of urban expansion and decentralization and from Puxi (west of the Huangpu River) to Pudong (east of the Huangpu River) as a result of significant economic development of the Pudong New Area. Both spatial diffusion and purpose diversification favor the convenience and flexibility of private motor vehicles. Driven by rapid motorization, vehicle travel is growing at a much faster pace than person travel. Overall, the annual growth rate for travel demand in Shanghai reached its peak in 2004 for both person trips and vehicle trips. In absolute numbers, person trip growth has peaked, but vehicle trip growth has not. In response to the growing demand, especially rapid motorization, the local government has made tremendous investments in road infrastructure and public transit, and it has attempted to manage demand through vehicle ownership control.
Keywords
Urban; Impacts; Policy