Master of Science / Department of Computer Science / Doina Caragea / The goal of the project is to create a database for storing the National Household Travel Survey (NHTS) data, and a user interface to query the database. Currently, the survey data is stored in excel files in the CSV format, which makes it hard to perform complex analyses over the data. Analyses of interest to transportation community include comparisons of the trips made by urban household to those made by rural household, finding the average trip time spent based on ethnicity, the total travel time of a particular household, the preferred vehicle by a specific household, average time spent per shopping trip, etc. The tool designed for the purpose of querying the NHTS database is a Python-based Web application. Django is used as the Web framework for this project and PostgreSQL is used for the back-end purpose. The user interface consists of various drop-down lists, text-boxes, buttons and other user interface components that facilitate querying the database and presenting the results in formats that allow easy interpretation. FusionCharts Django-Wrapper and FusionCharts Jquery-Plugin are used to visualize the data in the chart form. A Codebook of the NHTS dataset is also linked for the reference purpose at any point for the user. The tool built in the project allows the user to get a deeper understanding of the data, not only by plotting the data in the form of line charts, bar charts, two column graph, but also by providing the results of the queries in the CSV format for further analysis.

Individuals who use wheelchairs or who have other mobility challenges often are unable to access modern mobility systems "“ including application-based ride hailing and on-demand microtransit. Even designing a system targeted at these users is challenging, given the limited prior analysis of their travel behavior and activity patterns. Simulation tools are used by cities around the world to understand novel and complex transportation systems, yet few are including the needs of users with disabilities in these simulation studies. This thesis examines the travel patterns of wheelchair users from the 2017 National Household Travel Survey and presents a model of daily activity pattern choice of respondents who self-identify as using a wheelchair. This thesis discusses the application of a wheelchair status variable in the activity-based travel demand model ActivitySim and measures its effect on individual and household daily activity pattern choice. Wheelchair use is estimated to reduce the utility of a work daily activity pattern by 1.9 points relative to a home pattern for full time workers and 3.4 for part time workers. Including the effect of wheelchair use in a regional daily activity pattern model resulted in 21.9 percent of wheelchair users changing to a home activity pattern relative to a base scenario not including wheelchair use. Lastly, the thesis evaluates the performance of an on-demand, accessible mode for users with wheelchairs in the agent-based microsimulation BEAM. This simulation showed that demand for such a service increases linearly with fleet size and wait time remains constant, though further scenario refinement and research is necessary.

No description available.

Travel demand analysis has traditionally focused on exploring and modeling travel behavior on weekdays. This emphasis on weekday travel behavior analysis was largely motivated by the presence of well-defined peak periods, primarily associated with the journey to and from work. Most travel demand models are based on weekday travel characteristics and purport to estimate traffic volumes for daily or peak weekday conditions. Much of the planning and policy making that occurs in transportation arena in response to weekday travel behavior and forecasts. More recently, there had been a growing interest in exploring, understanding, and quantifying weekend travel characteristics. The ability to do this has been limited due to the non-availability of travel survey data that includes weekend trip information. Most travel surveys collect information about weekday travel behavior and ignore weekend days. However, the 2001 National Household Travel Survey includes a substantial sample that provided detailed trip information for weekend days and therefore this dataset offers a key opportunity to explore in-depth weekend travel characteristics. Weekend travel behavior is expected to be substantially different from the weekday travel behavior for difference in several spatial and temporal constraints. The difference in constraints can also lead to a change in trip chaining patterns on weekdays and weekends. Differences in constraints coupled with socio-economic changes characterized by greater disposable income, time-constrained lives, and greater discretionary activity opportunities point towards the growing role that weekend travel behavior is going to play in transportation planning and policy-making. This thesis provides a comprehensive analysis of weekend travel behavior using the 2001 NHTS. Differences and similarities between weekday and weekend travel behavior are identified and presented for different urban areas sizes varying according to Metropolitan Statistical Area (MSA) size. Models of weekend and weekday travel behavior are developed to capture the structural relationship of socio-demographics, activity durations, and travel duration are developed using structural equations modeling approaches to better understand the relationships among these aspects of travel behavior on weekdays and weekends. This report is supposed to act as an updated data guide to the National Cooperative Highway Research Program's (NCHRP) Report 365 titled "Travel Estimation Techniques for Urban Planning" aims at studying the changes in behavioral characteristics between two categories of the day of week - a weekday and a weekend based on personal, household and trip characteristics.

Recent developments in microsimulation modeling of activity and travel demand have called for the explicit recognition of time-space constraints under which individuals perform their activity and travel patterns. The estimation of time-space prism vertex locations, i.e., the perceived time constraints, is an important development in this context. Stochastic frontier modeling methodology offers a suitable framework for modeling and identifying the expected vertex locations of time space prisms within which people execute activity-travel patterns. In this work, stochastic frontier models of time space prism vertex locations are estimated for samples drawn from a household travel survey conducted in 2001 in the city of Thane on the west coast of India and National Household Travel Survey 2001, United States. This offers an opportunity to study time constraints governing activity travel patterns of individuals in a developing as well as developed country context. The work also includes comparisons between males and females, workers and non-workers, and developed and developing country contexts to better understand how socio-economic and socio-cultural norms and characteristics affect time space prism constraints. It is found that time space prism constraints in developing country data set can be modeled using the stochastic frontier modeling methodology. It is also found that significant differences exist between workers and non-workers and between males and females,possibly due to the more traditional gender and working status roles in the Indian context. Finally, both differences and similarities were noticed when comparisons were made between results obtained from the data set of India and United States. Many of these differences can be explained by the presence of other constraints including institutional, household, income, and transportation accessibility constraints that are generally significantly greater in the developing country context.

Literature on transportation planning and modeling is replete with the concept of a travel time budget. According to this concept, average daily travel times tend to be relatively constant. However, evidence from the 1983 Nationwide Personal Transportation Survey and the 2001 National Household Travel Survey suggest that the average daily travel time has increased by 1.9 minutes per year. Understanding travel time expenditures is important for forecasting travel demand, especially future vehicle miles of travel. Historically, travel demand models considered vehicle availability and income as limiting factors for travel, but going forward time may be the constraint. As individuals spend more time devoted to travel, less time will be available for other activities. Therefore, future travel demand is dependent on people's willingness to spend time traveling. Growth of travel demand has been per capita based not just population based. This has been enabled by several cultural trends, including fewer children to care for; specialization of activities; multitasking during travel, for example, cell phone use can add value to travel time; seeking socialization away from home; and increases in real income enabling more activity participation. This study will report the increase in average daily travel time expenditures and analyze the increase by various demographic segments of the population. Travel time expenditures are also related to activity participation, the characteristics of the area, and many other interrelated factors at the person level. Aggregate values will be used to investigate the general relationships between daily travel time expenditures and socio-demographic characteristics. Careful consideration of the implications of the increase in travel time, as well as the changes in society that have contributed to these changes will be explored. The increase in travel time expenditures is likely to play a significant role in future travel demand growth in the United States and will impact the performance of the transportation system going forward. If travel time expenditures continue to grow, the hope for slowing VMT growth may not materialize. Understanding the mechanics of why people are traveling more will aid planners and modelers in estimating future travel demand.

High precision data from household travel survey (HTS) is extremely important for the transportation research, traffic models and policy formulation. Traditional methods of data collection were imprecise because they relied on people’s memories of trip information, such as date and location, and the remainder data had to be obtained by certain supplemental tools. The traditional methods suffered from intensive labor, large time consumption, and unsatisfactory data precision. Recent research trends to employ smartphone apps to collect HTS data. In this study, there are two goals to be addressed. First, a smartphone app is developed to realize a smartphone-based method only for data collection. Second, the researcher evaluates whether this method can supply or replace the traditional tools of HTS. Based on this premise, the smartphone app, TravelSurvey, is specially developed and used for this study. TravelSurvey is currently compatible with iPhone 4 or higher and iPhone Operating System (iOS) 6 or higher, except iPhone 6 or iPhone 6 plus and iOS 8. To evaluate the feasibility, eight individuals are recruited to participate in a pilot HTS. Afterwards, seven of them are involved in a semi-structured interview. The interview is designed to collect interviewees’ feedback directly, so the interview mainly concerns the users’ experience of TravelSurvey. Generally, the feedback is positive. In this study, the pilot HTS data is successfully uploaded to the server by the participants, and the interviewees prefer this smartphone-based method. Therefore, as a new tool, the smartphone-based method feasibly supports a typical HTS for data collection.

The Texas state gas tax has been 20.0 cents per gallon since 1991, and the federal gas tax has been 18.4 cents per gallon since 1993. The gas tax is not only stagnant, but depreciating in value due to inflation. Thus, damage is being done to the infrastructure but the money needed to maintain and improve roadways is not being adequately generated. One proposed alternative to the gas tax is the creation of a vehicle miles traveled (VMT) fee; with equity being a crucial issue to consider. This research used 2009 National Household Travel Survey (NHTS) Texas data to consider the equity impacts surrounding four VMT fee scenarios. Data were filtered and weighted to reflect results representative of Texas vehicle-owning households in 2008. Each scenario was run both statically and dynamically under the assumption that the VMT fee would replace the state gas tax. An assessment of the relative vertical equity of each scenario was made by calculating the Gini Coefficient associated with the proportion of state gas tax or VMT fee revenue generated by each household income level quintile. Results indicate that all VMT fee scenarios are essentially as equally vertically equitable than the current state gas tax system. Scenario 4 was designed to be inherently horizontally equitable because the per mile fee associated with each roadway type (urban or rural) was assessed to all vehicles driven on these roadway types at a rate calculated to generate needed funds to address the mobility and infrastructure needs of that roadway type. Scenario 3, a scenario favoring vehicles with high fuel efficiency, was found to be the least horizontally equitable. Scenarios 2-4 were able to generate additional revenue desired to meet the infrastructure and mobility needs of Texas set forth by the 2030 Texas Transportation Needs Committee. The large fee increase necessary to achieve the desired additional revenue may not be popular or possible. However, an evaluation of the philosophy governing each scenario designed to generate additional revenue is informative when it comes to equity impacts. No one VMT fee scenario affects all household income levels and geographic locations uniformly and it was not the goal of this research to design an equitable VMT fee scenario. Rather, the effect of each scenario on 2008 Texas vehicle-owning households disaggregated by household income level and geographic location are presented and left to the discretion of elected officials to decide which VMT fee, if any, would be best for their constituents.

No description available.

Die vorliegende Dissertationsschrift geht der Frage nach, wie die Qualität von Haushaltsbefragungen zum Verkehrsverhalten bestimmt, bewertet und für zukünftige Erhebungen sichergestellt werden kann. Dabei spielt die Teilnahmebereitschaft als ein bedeutsamer, keinesfalls aber alleiniger Qualitätsindikator eine wichtige Rolle. Eine zentrale Forschungsfrage der Arbeit beschäftigt sich mit der Eignung gruppenspezifischer Ansprache und Befragung zur Erhöhung der Befragungsqualität. Ausgehend von grundsätzlichen Betrachtungen zu Bedeutung, wesentlichen Designelementen und insbesondere Fehlerquellen von Befragungen in der empirischen Sozialforschung, sind verschiedene Ansätze zur Einschätzung der Qualität einer Befragung Gegenstand dieses Teils der Arbeit. Darauf aufbauend werden stichtagsbezogene Haushaltsbefragungen zum Verkehrsverhalten im Alltag als Spezialfall von Befragungen eingeführt und Ansätze zur Qualitätssicherung bei derartigen Haushaltsbefragungen zusammengetragen. Eine Gegenüberstellung von Designelementen und möglichen Fehlern bei Verkehrsverhaltensbefragungen ermöglicht die Identifizierung und Beschreibung von neun Handlungsfeldern. Im Kontext von Erkenntnissen aus der Erhebungspraxis sowie Erfahrungen bei der Durchführung mehrerer Durchgänge des Forschungsprojektes „Mobilität in Städten – SrV“ wird eingeschätzt, inwieweit die jeweiligen Handlungsfelder zur Verminderung von Fehlereinflüssen und zur Qualitätssicherung beitragen können. Auf dieser Grundlage werden konkrete Handlungsoptionen ausgewählt. Für die Einschätzung der Handlungsoptionen hinsichtlich ihrer Wirksamkeit bei der Sicherung und Steigerung der Erhebungsqualität können auf Basis umfangreicher Literaturauswertungen insgesamt 24 Qualitätsindikatoren zusammengestellt werden. Diese ermöglichen die systematische Bewertung der Erfassungs-, Inhalts- und Durchführungsqualität. Unter Einbeziehung der Untersuchungsgruppen und Qualitätsindikatoren wird in einer vertieften empirischen Analyse untersucht, in welchem Maße die ausgewählten Handlungsoptionen zur gruppenspezifischen Ansprache und Befragung geeignet sind und ob sich dadurch die Erhebungsqualität steigern lässt. Neben umfangreichen Gruppenvergleichen findet eine Befragungssimulation nach der Monte-Carlo-Methode statt. Die Datenbasis dieser Analysen besteht überwiegend aus den Erhebungsdurchgängen und Sondererhebungen von „Mobilität in Städten – SrV“. Im Ergebnis der Analysen lassen sich Empfehlungen für die Weiterentwicklung von Haushaltsbefragungen zur Erfassung von Verkehrsverhaltensdaten ableiten. Diese gliedern sich in einen gruppenübergreifenden Teil und einen Abschnitt für spezielle Gruppen. Noch vorangestellt ist die klare Empfehlung, bei Haushaltsbefragungen zukünftig nur noch eine Person des Haushalts zu ihren Wegen am Stichtag zu befragen. Dieses Vorgehen erleichtert die zukünftige Implementierung (sogar trennscharfer) gruppenspezifischer Ansätze deutlich. Die zusammengestellten Empfehlungen bieten eine konsistente, praktikable und auf andere Befragungen übertragbare Basis, das Erhebungsdesign bestehender und zukünftiger Haushaltsbefragungen zum Verkehrsverhalten so anzupassen, dass durch die vollständige oder zumindest teilweise Umsetzung gruppenspezifischer Ansätze eine Verbesserung der Erhebungsqualität insgesamt erzielt werden kann. / This dissertation addresses the question of how the quality of household travel surveys can be determined, evaluated, and ensured for the development of future surveys. The willingness of individuals to participate is an important, but by no means exclusive, indicator of quality. A central research question of this work deals with the concept of combining group-specific survey methods to increase survey quality. Beginning with some fundamental terminological considerations, this work then focuses on essential design elements and, in particular, sources of error in surveys in empirical social research in order to establish various approaches for assessing the quality of a survey. Building on this, household travel surveys are introduced in specific examples, and approaches for quality assurance in such household travel surveys are compiled. A comparison of design elements and possible errors in household travel surveys provides for the identification and description of nine areas of activity. In the context of findings from the surveying practice as well as experience in conducting several waves of the research project "Mobility in Cities – SrV", the extent to which the respective fields of action can contribute to the reduction of errors and to quality assurance was assessed. On this basis, concrete options for action were selected. In order to evaluate the courses for action in terms of their effectiveness in securing and increasing the quality of surveys, a total of 24 quality indicators were compiled on the basis of extensive literature review. These allowed for the systematic assessment of three areas: quality of collection, content, and of application. With the involvement of analysis groups and quality indicators, a detailed empirical analysis was carried out to examine the extent to which the selected courses for action are suitable for group-specific combinations of survey methods and whether this can increase survey quality. In addition to extensive group comparisons, a survey simulation was implemented using the Monte Carlo method. The data foundation for these analyses primarily consisted of the surveys carried out for the research project "Mobility in Cities – SrV". These analyses enabled the establishment of recommendations which further the development of household travel surveys; these were divided into a cross-group section as well as a section for specific groups. Prior to these recommendations, it became clear that for future household travel surveys, only one individual in the household should be questioned regarding their trips on specific reference days. This decision significantly facilitates the future implementation of (even more selective) group-specific approaches. The compiled recommendations provide a consistent, practical foundation that can be applied to other surveys in order to adapt the design of existing and future household travel surveys, thus providing an overall or at least partial implementation of group-specific approaches which can improve overall survey quality.