conference paper
conference paper
Working from home (WFH) increased tremendously after the outbreak of the COVID-19 pandemic. A critical research need is to understand the associated impacts on travel behavior in the post-pandemic era, particularly on Vehicle Miles Traveled (VMT). In this context, we conceptualized a causal structure to investigate the interrelationships between WFH and VMT by considering non-work trip rates and travel efficiency as mediator variables. Travel efficiency is introduced as a latent factor, defined as a sustainability measure consisting of four indicators: activity-trip ratio, proportion of short-distance trips, proportion of micro-mobility trips, and proportion of travel time in non-auto modes. By applying a Structural Regression model based on the 2022 National Household Travel Survey data, we derived both direct and indirect effects of WFH on VMT. The indirect effect of WFH on VMT via non-work trip rates suggests that the frequency of non-work trips increases with the frequency of WFH, leading to an increase in VMT. On the other hand, the indirect effect of WFH on VMT via travel efficiency revealed that more WFH days induced more sustainable travel choices and thus contributed to reductions in VMT. The direct effect of WFH on VMT appeared negative, and the summation of both direct and indirect effects also resulted in a negative total effect of WFH on VMT. The findings of this study will provide important insights into the WFH arrangements and their impacts on travel behavior from several demand and performance measure perspectives, which will help policymakers formulate relevant post-pandemic transportation policies.
published journal article
conference paper
working paper
The purpose of this paper is to estimate the welfare effects of instituting nationwide marginal cost pricing for heavy highway vehicles, with marginal costs defined as the incremental contribution of a vehicle to repaving costs. We first describe such a tax, using existing evidence on the marginal costs of various vehicle movements. Next; we outline a procedure for estimating the tax’s impact on the distribution of vehicle-miles traveled by different types·of heavy trucks, and on shippers’ modal choice between truck and other forms of freight transportation. We then show how to calculate net benefits and the distribution of costs and benefits among shippers, carriers, and the public treasury. These calculations are carried out using 1982 data. Despite an atteMpt to be conservative throughout. we find that such a tax could go a long way toward solving the physical and financial problems of maintaining a sound infrastructure.
conference paper
published journal article
Phd Dissertation
Use of Advanced Traveler Information Systems (ATIS) is considered a promising way to improve traffic condition by helping travelers to efficiently use existing transportation facilities. Unlike other components of advanced management systems, the effectiveness of traveler information technologies is determined primarily by the traveler’s awareness of the information, correct interpretation of the information, evaluation of its usefulness, and implementation of the recommended course of action. The problems to be studied in this research are: what information to provide, when, where, and what for. The research examines a wide variety of information dissemination schemes under technologies such as in-vehicle navigation systems, changeable message signs, GPS-based location systems and wireless or Internet based vehicle communication and routing. This study evaluates various route guidance systems via static and dynamic network optimization and traffic simulation models. Parametric studies are conducted on certain aspects, due to the lack of good models on driver response/compliance to ATIS information.,This study formulates mathematical problems for the evaluation of both IVNS and CMS as mixed equilibrium traffic assignment problems and evaluates two different route guidance objectives (User Equilibrium and System Optimum) by employing driver’s compliance model with varied level of unguided drivers’ perception error and market penetration. This study also formulates dynamic optimal route guidance problems and incorporates route guidance strategies into dynamic traffic simulation model. Performance of route guidance strategies for IVNS and CMS are compared via parametric simulation experiments. Special interest of the research is to investigate marketability and effectiveness of private information suppliers who are capable of monitoring traffic condition from their subscribers. The research addresses many issues involved in ATIS dissemination from standpoints of both theoretical evaluation and practical implementation. The dissertation also develops preliminary insights on networks with multiple information service vendors and the complex dynamics that result from it, which is valuable for future research and deployment of ATIS. The research methodology incorporates non-linear network optimization algorithms, heuristic optimizations as well as large network simulation schemes.
published journal article
published journal article