Since the beginning of the 21st Century, the world has seen the rapid development of the so-called "sharing economy" or collaborative consumption (Botsman, 2010). One of the first areas affected by the shared economy is vehicle ownership. With the emergence of several new providers of mobility services, such as Uber and car2go, there has been the promise of changes to the traditional way of owning and using a vehicle (Wong, Hensher, & Mulley, 2017). One potential consequence of shared mobility services is the reduction in vehicle ownership. At the same time, cities are trying to anticipate these changes by reducing the amount of space dedicated to parking, including parking requirements for residential developments. This thesis aims to assess the extent to which new shared mobility services (specifically, carsharing, bikesharing, and ridehailing) and travel demand management strategies (especially parking requirements and transit pass availability) relate to vehicle ownership among residents of multifamily dwellings. To do this, we use a web-based survey targeted to residents of multifamily apartments from Portland, Oregon. With these data, we built a multinomial logistic of the number of the vehicles owned as a function of socio-demographics, built environment, parking supply, transit passes, and three forms of shared mobility services. Results suggest that there is a strong association between shared mobility use and car ownership. However, it is not as significant as the effects of income, household size, distance to work, transit pass ownership, or even parking availability. Carshare use was negatively associated with the number of household vehicles, suggesting that it may be a useful tool in reducing car ownership. For respondents with higher education and income levels, increased carshare use was associated with fewer cars. Ridehail use, however, was not as clearly associated with reducing vehicle ownership and the effect was much smaller than that of carsharing. Parking availability in the building also has a significant and positive association with vehicle ownership. In sites with no parking available, there is an increased chance of the household owning less than two or more vehicles. However, this effect seems to disappear with the increased use of shared mobility. For all income levels, monthly use of ridehail and carshare between two and three times may decrease the odds of owning two or more vehicles. The use of both options, relaxing parking requirements and shared mobility availability, seems the best strategy to reduce vehicle ownership. In the short term, it is an alternative to those residents that decide to get rid of one or all cars but still are not ready to give up using cars. For the long term, a new relationship with vehicle ownership can be built now for the younger generation.

Thesis (Ph.D. (Town and Regional Planning))--North-West University, Potchefstroom Campus, 2008.

The aim of this thesis was to study determinants of a readiness for pro-environmental travel behavior in households. Four empirical studies were conducted examining reduction in car use (Study I), acceptability of transport policy measures (Study II and III), and behavioral adaptations in response to travel demand management (TDM) measures (Study IV). In Study I, the aim was to interrupt habitual car use by means of a deliberation intervention and to examine the importance of moral motivation (i.e., personal norm) for car use reduction. Results showed that, as a result of the intervention, car use was mainly reduced among car users with a strong car use habit and a strong moral motivation to reduce car use. The aim of Study II was to examine factors important for the acceptability of three TDM measures: raised tax on fossil fuel, improved public transport, and an information campaign. The results demonstrated the importance of general environmental beliefs (i.e., pro-environmental orientation, problem awareness, personal norm, and willingness to reduce car use) and policy specific beliefs (i.e., perceived impact on freedom to choose travel mode and own car use, perceived effectiveness, and perceived fairness) for the acceptability of the measures. Furthermore, personal norm was found to be particularly important for the acceptability of raised tax and the information campaign, whereas problem awareness was more important for the acceptability of improved public transport. Following up on Study II, the purpose of Study III was to examine the acceptability of single and combined transport policy measures, more specifically, raised tax on fossil fuel, improved public transport, subsidies of renewable fuel, a package of raised tax on fossil fuel and improved public transport, and a package of raised tax on fossil fuel and subsidies of renewable fuel. General environmental beliefs (i.e., pro-environmental orientation, problem awareness, personal norm, and willingness to act) and policy specific beliefs (i.e., perceived effectiveness and perceived fairness) were found to be important for the acceptability of the measures. Moreover, personal norm was particularly important for the acceptability of raised tax on fossil fuel and the packages, while problem awareness was more important for the acceptability of improved public transport and subsidies of renewable fuel. The aim of Study IV was to examine the behavioral adaptations, more specifically, the expected car use reduction, in response to three hypothetical TDM measures: raised tax on fossil fuel, improved public transport, and a package of raised tax on fossil fuel and improved public transport. Furthermore, factors important for the expected car use reduction were analyzed. Results showed that a combination of the measures was expected to lead to a larger car use reduction compared to the single measures, and the most commonly chosen reduction strategies were more efficient car use and changing travel mode. Moreover, internal motivational factors, such as personal norm, and the perceived personal impact of the measures were important for expected car use reduction in response to the measures.

As transportation policies are changing to encourage alternative modes of transportation to reduce congestion problems and air quality impacts, more planning organizations are considering or implementing activity-based travel demand models to forecast future travel patterns. The proclivity towards operating activity-based models is the capability to model disaggregate travel data to better understand the model results that are generated with respect to the latest transportation policy implementations. This thesis first examines the differences between the two major modeling techniques used in the United States and then describes the assessment tool that was developed to recommend whether a region should convert to the advanced modeling procedures. This tool consists of parameters that were decided upon based on their known linkages to the advantages of activity-based models.

This research develops a framework to estimate the effective sample size of Global Positioning System (GPS) based panel surveys in urban travel behavior studies for a variety of planning purposes. Recent advances in GPS monitoring technologies have made it possible to implement panel surveys with lengths of weeks, months or even years. The many advantageous features of GPS-based panel surveys make such surveys attractive for travel behavior studies, but the higher cost of such surveys compared to conventional one-day or two-day paper diary surveys requires scrutiny at the sample size planning stage to ensure cost-effectiveness. The sample size analysis in this dissertation focuses on three major aspects in travel behavior studies: 1) to obtain reliable means for key travel behavior variables, 2) to conduct regression analysis on key travel behavior variables against explanatory variables such as demographic characteristics and seasonal factors, and 3) to examine impacts of a policy measure on travel behavior through before-and-after studies. The sample size analyses in this dissertation are based on the GPS data collected in the multi-year Commute Atlanta study. The sample size analysis with regard to obtaining reliable means for key travel behavior variables utilizes Monte Carlo re-sampling techniques to assess the trend of means against various sample size and survey length combinations. The basis for the framework and methods of sample size estimation related to regression analysis and before-and-after studies are derived from various sample size procedures based on the generalized estimating equation (GEE) method. These sample size procedures have been proposed for longitudinal studies in biomedical research. This dissertation adapts these procedures to the design of panel surveys for urban travel behavior studies with the information made available from the Commute Atlanta study. The findings from this research indicate that the required sample sizes should be much larger than the sample sizes in existing GPS-based panel surveys. This research recommends a desired range of sample sizes based on the objectives and survey lengths of urban travel behavior studies.

Several research projects all over the world have considered transport pricing measures and policies as promising attempts to solve urgent traffic problems in urban areas. One important precondition for the successful implementation of pricing strategies is public acceptability. However, empirical findings have shown that the acceptability of such strategies in general is very low. Aim of this dissertation is to analyse the reasons for the low acceptability of road pricing. The dissertation is organized as follows: Firstly, the problems related to transport and the measures to cope with these problems are outlined. The focus is thereby on economic measures such as road user fees, whose economic and traffic-related assumptions are discussed. Then, a definition of the terms used is given and main European results concerning the current acceptability level of various travel demand management (TDM) strategies are reported. Moreover, a theoretical framework is developed which attempts to identify the essential factors determining transport pricing acceptability. In two empirical studies (N1 = 923, N2 = 667), it is investigated whether and to what extent these factors contribute to the explanation of acceptability. Finally, conclusions are drawn and some recommendations for future research are given. / Straßenbenutzungsgebühren für den privaten Autoverkehr sind vielfach als sinnvoll und wünschenswert vor allem zur Lösung der zahlreichen Verkehrsprobleme in städtischen Ballungsräumen begründet worden. Bisher ist es jedoch nicht zu einer nennenswerten Umsetzung dieser Maßnahmen gekommen. Es herrscht in der Literatur Einigkeit, daß die geringe Akzeptanz von Straßenbenutzungsgebühren in der Bevölkerung und die deutliche Ablehnung bei den betroffenen Autofahrern die wesentlichen Gründe für den fehlenden politischen Willen sind, road pricing einzuführen. Ziel dieser Arbeit war es, die Ursachen und Bedingungen für die mangelnde Akzeptanz von Straßenbenutzungsgebühren bei den betroffenen Autofahrern zu untersuchen. Die Arbeit ist wie folgt aufgebaut: Im ersten Abschnitt wird die Ausgangslage und der Problemhintergrund dargestellt. Es wird erläutert, welche negativen Konsequenzen des motorisierten Individualverkehrs vorliegen, und mit welchen Maßnahmen ihnen begegnet werden kann. Der Fokus liegt dabei auf preispolitischen Maßnahmen wie Straßenbenutzungsgebühren, dessen ökonomische und verkehrswissenschaftliche Annahmen dargestellt werden. Dem gegenübergestellt wird die gesellschaftspolitische Realität: zum einen in Form der massiven Ablehnung von Straßenbenutzungsgebühren durch Bevölkerung und betroffene Autofahrer und zum anderen in Form der zahlreichen, erfolglosen und gescheiterten Versuche, Straßenbenutzungsgebühren einzuführen. Dies mündet in die Ableitung erster Forschungsfragen und in die Entwicklung des Untersuchungsansatzes. Im darauf folgenden Abschnitt werden die theoretischen Grundlagen zur Untersuchung der Akzeptanz von Straßenbenutzungsgebühren gelegt. Dabei wird zunächst geklärt, wie sich der Begriff "Akzeptanz" definieren läßt und in welche relevanten psychologischen Theorien er sich einordnet. Im Anschluß wird das Modell zur Akzeptanz von Schlag vorgestellt und analysiert. Darauf aufbauend werden die zentralen Variablen des Modells auf ihre theoretische und empirische Relevanz und unter Berücksichtigung potentiell konkurrierender Ansätze dargestellt und untersucht. Ziel ist die Klärung der logischen und kausalen Struktur des Modells und der Beziehungen der Variablen untereinander. Dies führt schließlich in die Ableitung überprüfbarer Hypothesen in Form eines erweiterten Akzeptanzmodells. Zur Überprüfung des Modells, der aufgestellten Hypothesen und Forschungsfragen werden zwei Untersuchungen berichtet (N1 = 923, N2 = 667), die inhaltlich aufeinander aufbauen. Diese wurden im Rahmen der EU-Forschungsprojekte TransPrice und AFFORD durchgeführt. Generelles Ziel ist die Validierung der Modellkonstrukte und ihrer angenommenen Beziehungen. Im letzten Abschnitt werden zusammenfassend und basierend auf den beiden Studien die wesentlichen Ergebnisse rekapituliert, sowie offene Forschungsfragen und Anforderungen abgeleitet, die sich zukünftigen Studien stellen. Schließlich wird diskutiert, welche Implikationen sich aus dieser Untersuchung ziehen lassen und welche Aspekte zu berücksichtigen sind, wenn Straßenbenutzungsgebühren der Öffentlichkeit präsentiert werden. - Die Druckexemplare enthalten jeweils eine CD-ROM als Anlagenteil: 490 KB - Nutzung: Referat Informationsvermittlung der SLUB

Urban traffic congestion is recognised as a major problem by most people in world cities. However, the implementation of congestion reducing measures on a wide scale eludes most world cities suffering from traffic congestion, as many oppose the notion of road pricing and despite economists and transportation professionals having advocated its benefits for a number of decades. The effects of road pricing have attracted considerable attention from researchers examining its effects, as it is thought to hold the key in understanding and overcoming some inherent obstacles to implementation. Unfortunately, many of the attempts consider the effects in isolation and with hypothetical, idealised and analytical tools, sometimes loosing sight of the complexities of the problem. This research empirically investigates the effects of road pricing in London, and identifies factors, which may prove to sustain it as a traffic reduction instrument. The results indicate that an integrated approach has to be developed and implemented, based upon the recognition of local perceptions, concerns, aspirations and locally acceptable solutions, if the acceptance of road pricing is to be improved. The key to dealing with the effects of road pricing, is to encourage a concerted effort by various stakeholders developing strategies considering a range of differing initiatives, coordinating and managing them in the realm of the political-economic context in which they exist. / Thesis (M.Art. et Scien. (Town and Regional Planning))--North-West University, Potchefstroom Campus, 2005.

Urban traffic congestion is recognised as a major problem by most people in world cities. However, the implementation of congestion reducing measures on a wide scale eludes most world cities suffering from traffic congestion, as many oppose the notion of road pricing and despite economists and transportation professionals having advocated its benefits for a number of decades. The effects of road pricing have attracted considerable attention from researchers examining its effects, as it is thought to hold the key in understanding and overcoming some inherent obstacles to implementation. Unfortunately, many of the attempts consider the effects in isolation and with hypothetical, idealised and analytical tools, sometimes loosing sight of the complexities of the problem. This research empirically investigates the effects of road pricing in London, and identifies factors, which may prove to sustain it as a traffic reduction instrument. The results indicate that an integrated approach has to be developed and implemented, based upon the recognition of local perceptions, concerns, aspirations and locally acceptable solutions, if the acceptance of road pricing is to be improved. The key to dealing with the effects of road pricing, is to encourage a concerted effort by various stakeholders developing strategies considering a range of differing initiatives, coordinating and managing them in the realm of the political-economic context in which they exist. / Thesis (M.Art. et Scien. (Town and Regional Planning))--North-West University, Potchefstroom Campus, 2005.

Much has been written about the desperate need to seek alternative solutions to the urban traffic congestion problems we face today. To manage these problems, three main streams of intervention have evolved from supply, demand and land-use management paradigms. Whilst their underlying measures all have the ability to reduce traffic congestion one way or another, little has been done to integrate the measures of each stream using a qualitative decision framework or process enabling the selection of site specific measures appropriate to local traffic and transport conditions. To this end the study reports the results of an empirical investigation by which a Multi-Criteria Analysis based Dynamic Adaptive Decision Framework (D.A.D.F.) were developed. This screens selected measures identifying those that have the potential to alleviate site specific road based traffic congestion. The product of the screening process is a set of sustainable measures transposed into an integrated strategy tailored to address local traffic congestion issues. Once the D.A.D.F. was developed, its usefulness and workability was tested by applying it to a case study. The case study results demonstrated that the D.A.D.F. is capable of producing integrated strategies with the ability to manage traffic congestion, encourage sustainable development and alleviate some site specific development challenges within the context of the study areas. Going beyond developing the decision framework, the study recommends positioning the D.A.D.F. within the South African planning system as part of a Traffic Congestion Management Plan (T.C.M.P.), setting out its likely components within the local context. It is concluded that the main innovation of the study is the development of the D.A.D.F., the T.C.M.P., the recommendations to situate both in the planning system and the comprehensive, but still transparent, approach undertaken to create integrated strategies for specific local conditions consisting of elements that work together to produce cumulative short to long term effects that attain a balanced set of environmental, social and economic goals - all imperative for sustainable development. / Thesis (Ph.D. (Town and Regional Planning))--North-West University, Potchefstroom Campus, 2008.

Much has been written about the desperate need to seek alternative solutions to the urban traffic congestion problems we face today. To manage these problems, three main streams of intervention have evolved from supply, demand and land-use management paradigms. Whilst their underlying measures all have the ability to reduce traffic congestion one way or another, little has been done to integrate the measures of each stream using a qualitative decision framework or process enabling the selection of site specific measures appropriate to local traffic and transport conditions. To this end the study reports the results of an empirical investigation by which a Multi-Criteria Analysis based Dynamic Adaptive Decision Framework (D.A.D.F.) were developed. This screens selected measures identifying those that have the potential to alleviate site specific road based traffic congestion. The product of the screening process is a set of sustainable measures transposed into an integrated strategy tailored to address local traffic congestion issues. Once the D.A.D.F. was developed, its usefulness and workability was tested by applying it to a case study. The case study results demonstrated that the D.A.D.F. is capable of producing integrated strategies with the ability to manage traffic congestion, encourage sustainable development and alleviate some site specific development challenges within the context of the study areas. Going beyond developing the decision framework, the study recommends positioning the D.A.D.F. within the South African planning system as part of a Traffic Congestion Management Plan (T.C.M.P.), setting out its likely components within the local context. It is concluded that the main innovation of the study is the development of the D.A.D.F., the T.C.M.P., the recommendations to situate both in the planning system and the comprehensive, but still transparent, approach undertaken to create integrated strategies for specific local conditions consisting of elements that work together to produce cumulative short to long term effects that attain a balanced set of environmental, social and economic goals - all imperative for sustainable development. / Thesis (Ph.D. (Town and Regional Planning))--North-West University, Potchefstroom Campus, 2008.