METRANS Transportation Center

A fundamental justification for transit subsidies in the United States is to provide a basic level of mobility to all persons, especially the transportation disadvantaged: those who are either unwilling or unable to drive or who do not have access to a car. Yet even among the disadvantaged, most travel is by private vehicle. This paper examines the role of transit in the daily travel patterns of low-income households. Public transit is used for only a small portion of travel, and those who use transit regularly have the lowest level of mobility among all population segments. Attitudinal data indicate dissatisfaction with public transit, suggesting that current trends are likely to continue. Retaining existing markets by improving service frequency and quality in high-demand markets, exploring more effective ways of providing transit in low-demand markets, and expanding transit to serve off-peak and off-direction commutes would make transit a more attractive option for everyone.

The adoption of passenger leaders could make crowd evacuation in urban railway transit (URT) stations more efficient. The number, location, and the actions of the leaders are the most important elements in an evacuation strategy and have a great impact on evacuation efficiency. This paper proposes a hybrid bi-level model to optimize the number and initial locations of leaders as well as the routes of leaders during the evacuation, which explicitly incorporates the passengers' guidance demand and multi-leader coordination mechanism. The leaders' initial locations are generated by solving the maximal covering location problem (upper level model) and their evacuation routes are determined by a co-simulation heuristic approach (lower level model). The social force model and its modifications are used to model the dynamics of common evacuees, leaders, and followers in simulation models. The convergence performance of the proposed co-simulation heuristic approach and the effectiveness of the optimal evacuation strategy have been investigated and demonstrated using a case study of a typical island platform of Beijing's URT station. Three other evacuation strategies are considered for comparison purposes in order to show the influence of the number and initial locations of leaders as well as the multi-leader coordination mechanism during the evacuation process. Our analysis supported by simulations shows the following: 1) the optimal number of leaders exists for a given human cost and guidance demand constraints; 2) the distribution of leaders for maximal covering makes the evacuation of the followers more efficient; and 3) the proposed optimal evacuation strategy has better performance in terms of shorter evacuation time and higher utilization of exits compared with other considered strategies.

Abstract While evidence of polycentric urban form is extensive, questions remain regarding the value of agglomeration economies in an information economy, and hence whether polycentricity will persist over time. This paper examines employment spatial structure in four U.S. metropolitan areas between 1990 and 2009. We describe the spatial distribution of employment among centers and non‐center locations across time, examine the persistence of center boundaries, and test for monocentric and polycentric form via density gradient estimations. Results show that the four areas are all polycentric but of different degree. Despite some small fluctuations, metropolitan spatial structure is persistent even in the face of economic shocks in the 2000s: employment centers have not lost their importance and influence in the metro‐wide employment distribution over time.

ABSTRACT This study empirically investigates traffic congestion effects on agglomeration through the lens of firm location decisions. A discrete choice model is applied to examine new establishments’ location choices within the Los Angeles metropolitan area. Employment centers are defined as the choice set to explore the nature and role of intraurban agglomerations. The results show that metro‐wide congestion negatively affects the location choices of firms in the high‐order office‐related activities, while local congestion have positive impacts on those firms’ location decisions. In contrast, firms in production‐related activities are positively influenced by regional congestion but are negatively affected by local congestion levels.

The drive for seamlessness in freight transport is the subject of Leinbach and Capineri's Globalized Freight Transport: Intermodality, E-Commerce, Logistics and Sustainability. The hope is that fre...

Summary form only. Provides an overview of the technical articles and features of interest to readers that appear outside of this publication.

Presents the introductory editorial for this issue of the publication.

Summary form only. Provides an overview of the technical articles and features of interest to readers that appear outside of this publication.

Summary form only. Provides an overview of the technical articles and features of interest to readers that appear outside of this publication.

Summary form only. Provides an overview of the technical articles and features of interest to readers that appear outside of this publication.

Summary form only. Provides an overview of the technical articles and features of interest to readers that appear outside of this publication.

Increasing adoption of zero-emission vehicles (ZEVs) has raised concerns about potential disparities, including increased gentrification in low-income communities. As a first step in unraveling this rarely studied relationship, we examined the association between ZEV adoption and measures of gentrification. We addressed two questions: (1) How do ZEV adoption trends vary by neighborhood-level gentrification and disadvantage in California metropolitan areas? and (2) Among neighborhoods that are not already gentrified, is prior ZEV adoption associated with subsequent changes in housing prices? We obtained census tract-level data on longitudinal counts of battery electric vehicle (BEV) and plug-in hybrid electric vehicle (PHEV) registrations, median home value and monthly rent, disadvantaged communities (DACs) designations, and gentrification status ('none/early,' 'advanced/stable,' or 'exclusive'). Linear mixed models estimated BEV (or PHEV) adoption trajectories (2015-2023) across gentrification status between DAC and non-DAC, allowing nonlinear time trends. Among 'none/early' gentrification tracts, we related prior ZEV adoption (2015-2019) to subsequent (2020-2023) home values and rental prices using linear mixed models. ZEV adoption trends varied by gentrification in non-DAC tracts, while DACs had lower levels of ZEV adoption and less evidence for disparities. Among 'none/early' gentrification tracts, tracts with higher BEV (or PHEV) adoption were associated with larger absolute increases in home value compared to tracts in the lowest adoption quartile. These early findings support community concerns that ZEV adoption may influence housing costs and gentrification. Further research is needed on these complex relations and possible policy interventions.

Summary form only. Provides an overview of the technical articles and features of interest to readers that appear outside of this publication.