Elise Miller-Hooks

PhD Student:
Neza Vodopevic

Neza VodopevicPhD 2018, Civil and Environmental Engineering, UMD

Graduate Research Assistant, Sid & Reva Department of Civil, Environmental and Infrastructure Engineering
4400 University Drive, MS 6C1, George Mason University, Fairfax, VA 22030

Email: nvodopiv@gmu.edu

Dissertation Title:

Analytical techniques for addressing the impact of public transport service disruptions on transit-reliant populations

Recipient of the ITS Maryland Graduate Scholarship (2015)


This dissertation analyzes the public transportation system as a system with a diverse population of users. It quantifies the effects of travel time uncertainty, inadequate route coverage, and service disruption on system performance. It then proposes strategies for diminishing the effects of such circumstances on underserved users and optimizes the implementation of the strategies proposed.

Dial-a-ride services used to transport mobility-impaired populations exist worldwide. In this dissertation, dial-a-ride routes and schedules created under a deterministic travel time assumption are found to frequently violate quality-of-service constraints operationally. A recourse option that assigns taxis to those passengers who are likely to be picked up late is proposed. The optimal recourse policy is modeled as an optimal stopping problem and formulated as a stochastic dynamic program. Properties of the optimal policy are derived analytically, and its solution is approximated with a binomial lattice method used in the pricing of American options. Finally, a two-stage stochastic optimization approach is developed to show how the opportunity to take recourse dynamically might be integrated into a priori scheduling and routing.

Low-income workers face obstacles in attaining and maintaining steady employment. One barrier is that many do not own cars and find it difficult to access potential employers by public transit. This dissertation investigates job accessibility for low-income workers in five US cities and considers how this accessibility might be improved by way of demand-responsive transit. The approximate residence and work locations for 5,410 low-income workers were extracted from Census data. A web-based route planner was then used to generate information about commutes between these locations, first when traveling by car and then when using public transit. Finally, hypothetical dial-a-ride routes connecting home and work locations were created and assessed for user benefits and operating efficiency.

The resilience of a community to disruptions in a public transportation system depends not only on the technical system’s ability to maintain service levels, but also on the ability of individuals to cope with and adapt to disruptions. Different populations have different levels of flexibility, different adaptive strategies, and different emergent behaviors. In adapting, passengers rely on additional technical systems thereby creating interdependencies between the transit system and other technical systems. This dissertation considers transit resilience in the context of diverse populations of passengers who experience the system differently, but share its resources. It presents a conceptual framework for incorporating human actions and population characteristics in studying the resilience of interdependent technical systems. A methodology is developed for quantifying the resilience of a transit system and techniques from reliability theory are adapted for identifying which system components are critical for each population.

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Elise Miller-Hooks, Ph.D.
Bill & Eleanor Hazel Chair in Infrastructure Engineering

Phone: 703.993.1685
Email: miller@gmu.edu

Office: 4614 Nguyen Engineering Building

Sid and Reva Dewberry Department of Civil, Environmental and Infrastructure Engineering
George Mason University
4400 University Drive, MS 6C1
Fairfax, VA 22030

Additional Resources




Volgenau School of Engineering
George Mason University