Five Students Awarded Dissertation Grants for Spring 2010 Cycle
May 21, 2010—Five students at four UC campuses have been awarded UCTC Dissertation Grants for the Spring 2010 award cycle. Each grant provides the student with $20,000.
The dissertation grantees are: Weiha Gu (UC Berkeley), Lima Koptitch (UC Irvine), Edward Pultar (UC Santa Barbara), Robert Schneider (UC Berkeley), and Michael Smart (UCLA).
All proposals were reviewed, evaluated, and ranked independently by a former UCTC Dissertation Award grantee and a senior researcher in the field. Upon completion, links to the dissertations will be posted on the dissertation research page of UCTC Web site.
Models for Estimating Bus Stop Capacity
Weihua Gu, Doctoral Candidate, Department of Civil and Environmental Engineering, UC Berkeley
Advisor: Michael Cassidy
Project Description: The research will develop queueing models that predict the maximum rates that buses can discharge from busy stops, since this is a key indicator of a bus system's overall service quality. The queueuing models will estimate bus-stop capacities for a wide range of operating environments, bus-stop geometries, and input factors. In cases where analytical solutions are not possible, numerical approximations and computer simulations will be used as substitutes. The current literature on the subject is highly incomplete. We therefore expect that the proposed work will unveil key cause and effect relations, and we have recently made good progress in this regard. Ultimately, the models will aid transit agencies: when determining a suitable number of bus berths for a stop; or its ideal location relative to nearby traffic signals; or even when selecting policies for controlling the buses that use a particular stop.
Key Words: Bus stop capacity; bus stop queueuing.
An Analysis of the Impact of an Incident Management System on Secondary Incidents on Freeways - An Application to the I-5 in California
Lima Koptitch, Doctoral Candidate, Department of Civil and Environmental Engineering, UC Irvine
Advisor: Jean-Daniel Saphores
Project Description: Accidents are the largest source of external costs related to transportation with an estimated annual cost that exceeds $200 billion in the United States alone. Accidents lead to traffic backups that can result in secondary accidents. The purpose of this project is to investigate empirically whether the implementation of Changeable Message Signs (CMS), which belong to Intelligent Transportation System tools, can reduce secondary collisions by providing motorists with real-time traffic information. I will first review previously published methods of estimating secondary accidents to clarify the definition of secondary accidents and offer improvements. I will then study a 74-mile portion of Interstate 5 from the Mexico-US border to Orange County, CA that has 12 CMS, 3 of which are in southbound direction. This freeway has 4 to 6 lanes in each direction, and a maximum AADT volume of 230,000 vehicles. For this study area, I put together a unique dataset that includes accident data for year 2008 combined with detailed weather data. I will rely on counting and regression models to estimate the number of secondary incidents based on the number of primary accidents, weather conditions, time of day, traffic conditions and the availability of information.
Key Words: Accidents; secondary accidents; incident management; intelligent transportation system; changeable message signs.
The Synergy of Transportation, Social, and Data Networks
Edward Pultar, Doctoral Candidate, Department of Geography, UC Santa Barbara
Advisor: Martin Raubal
Project Description: This research examines travel behavior using Internet-based websites that provide free lodging with local inhabitants. Users of such systems utilize an amalgamation of transportation networks, social networks, and communication networks. This research focuses on how the geographical spread of people in a modern Internet-based social network influences the U.S. surface transportation travel choices of each individual in the network. This new subfield of travel will lead to transformative research on modern travel methodologies. This is partly because users are able to make more dynamic, mid-trip decisions due to the ubiquitous availability of the Internet. Also, the inclusion of reference systems and community message boards caters to highly flexible travel decisions. Broader impacts include a means for modern travelers to examine interaction and to facilitate trip planning. There is a need for understanding travel behavior for long distance travel combined with the use of information from a social network. Therefore this project will be a leading indicator of travel decision making of the future. Upon completion of this research innovative contributions will be made for:
- Cost and time budgets
- Location choice Destination and
- travel information using telecommunications and word of mouth in a social network.
Key Words: Social data networks; spatio-temporal time geography; travel behavior.
Understanding Mode Choice Decisions: Neighborhood Characteristics and Trip Chaining
Robert J. Schneider, Doctoral Candidate, Department of City and Regional Planning, UC Berkeley
Advisor: Robert B. Cervero
Project Description: Over the past two decades, many United States communities have established policies to reduce private automobile use and increase the proportion of travel done by walking and bicycling. While some local strategies have resulted in more walking and bicycling in specific neighborhoods and for particular groups of people, broad modal shifts have not occurred. The private motor vehicle is the most common transportation mode used in every metropolitan region in the United States.
The study will use a mixed-methods approach to explore how people make mode choice decisions. It will focus on the influence of neighborhood characteristics (land use, crash risk, crime risk, and aesthetics) and trip-chaining patterns (convenience) on mode choice. Quantitative data will be gathered from a survey of approximately 1,000 customers at Walgreens retail pharmacy stores in 20 San Francisco Bay Area neighborhoods. Qualitative interviews will be done to develop a richer understanding of how individual attitudes, family responsibilities, and time constraints influence people's mode choices for shopping trips. Results will provide new methods to quantify multimodal travel, identify specific neighborhood and site characteristics that are associated with walking and bicycling, and suggest strategies to increase pedestrian and bicycle use for routine neighborhood travel.
Key Words: Sustainability; multimodal transportation; neighborhood design; trip-chaining; mode choice.
Immigrant Ethnic Neighborhoods, Neighborhood Inward Focus, and Travel Mode Choice
Michael Smart, Doctoral Candidate, Department of Urban Planning, UC Los Angeles
Advisor: Evelyn Blumenberg
Project Description:Scholars have found that immigrants living in concentrated ethnic neighborhoods exhibit significantly "greener" travel patterns than the native-born, even after controlling for income, automobile availability, and the like. However, these studies have not differentiated ethnic neighborhood types, though the broader literature suggests considerable diversity in spatial and economic patterns within and across these neighborhoods. This dissertation seeks to tie together these literatures by explicitly modeling one aspect hypothesized to differentiate ethnic neighborhoods: the co-ethnic boundedness, or inward focus, of these neighborhoods. I hypothesize that this inward focus helps to explain the increased propensity of residents of ethnic neighborhoods to use alternative modes of transportation, such as public transportation, walking, and bicycling. Using previously unused microdata and a nested logit mode choice model, I first seek to validate prior findings on the independent effect of ethnic neighborhoods on mode choice. Next, focusing on the Los Angeles region, I differentiate these neighborhoods by the degree to which jobs and workers are co-bounded within the ethnic neighborhood, developing new measures to describe the degree to which ethnic economies function within a highly localized geographic area. Finally, I use these two measures to help determine the independent effects of neighborhood on travel mode choice.
Key Words: Immigration; neighborhood type; mode choice; ethnic economies.
