Jiawen Yang

Spatial heterogeneous impact of built environment on household auto ownership levels: evidence from analysis at traffic analysis zone scales

Household auto ownership modeling plays an important role in travel demand analysis because it reveals a key link between travel behavior and built environment. The object of this paper is to estimate the impact of built environment on household auto ownership levels by using a multilevel, mixed ordered probit model, which captures the spatial heterogeneity across traffic analysis zones (TAZs). Parameters are estimated with Bayesian estimation method via Markov Chain Monte Carlo (MCMC) sampling. The data come from the household travel survey 2007–2008 for the Washington–Baltimore Region. Empirical results indicate that our multilevel ordered probit model can effectively address the spatial heterogeneity across zones and provide better model fit than traditional ordered probit model. It is found that built environment can explain about 42.8% of the spatial heterogeneity in household auto ownership. Our findings can help policy makers develop a better understanding of how the built environment can influence household auto ownership.

Measuring the spatiotemporal variation and evolution of transport network of China’s megaregions

Megaregion has become a prominent feature of modern China. Reflecting upon China’s recent path of transport infrastructure construction, this research examines the spatiotemporal characteristics of transport network development and its accessibility impacts in China’s ten megaregions from 1982 to 2010. Using historical transport network data and multiple national censuses (1982, 1990, 2000 and 2010), we computed two levels of indicators of megaregional transport network: megaregion level and county level, and analyzed the intra-megaregion and inter-megaregion disparities of transport network of the ten megaregions of China. Transport networks at the megaregion level are measured by three indicators: 1) transport network density; 2) infrastructure endowment per capita; and 3) size of transport network’s standard ellipse. Two accessibility indicators for measuring transportation network at the county level are calculated: weighted average travel time and potential accessibility. The research results show the following: 1) Road and rail network densities witnessed the greatest growth during the 2000–2010 period, and growth was more significant for railway network. 2) By 2010, average road endowments per capita in inland megaregions became higher than in coastal megaregions, while average rail endowments per capita in coastal megaregions became higher than in inland megaregions. 3) The sizes and directions of the standard deviational ellipses of road and rail network changed continuously during the study period. However the changes of road network ellipses were relatively small, while the changes of railway network ellipses were more significant. 4) Megaregions have all benefited significantly from transportation infrastructure improvement in the past few decades in terms of WATT and potential accessibility, but the three giant megaregions benefited most.

Assessing Motor Vehicle Quota Policies in China: Social Welfare Perspective

Seven cities in China employ vehicle quota policies (VQPs) to mitigate urban traffic congestion. In these cities, vehicle licenses are allocated through a lottery, auction, or a mixture of the two. This study performs a policy assessment of China’s VQP with a social welfare perspective. It is argued that the issue is relevant to the selection of different modes of resource allocation, since an auction can match the precious resource with the individuals who value it most whereas a lottery meets the social expectation of equity. From the broad perspective of urban transportation, both auction- and lottery-based VQPs can be further improved by changing supplemental policies relevant to lottery entry, auction revenue usage, and vehicle purchase timing. VQPs should be used to help but not to replace travel demand management. As more cities in China adopt VQPs, this research can inform future policy making.

Path Planning with Information on Travel Time Reliability

The shortest path under a given on-time arrival probability is valuable to travelers wishing to save time and avoid traffic uncertainty. Conventional reliable shortest path methods often assume that travel time follows normal distribution, but substantial evidence shows that travel time in peak periods follows lognormal distribution. This paper proposes a reliable shortest path method under the assumption that travel time in peak periods follows lognormal distribution. Due to the character of bi-objective optimization, first-order stochastic dominance was conducted to compare the priority of a set of paths. Then, an improved RSPP-LC algorithm that simplifies the path-correcting procedure was constructed and applied to a small network in Shenzhen. The computational result indicates that RSPP-LC algorithm performs well in a small-scale network.