• Refine Query
  • Source
  • Publication year
  • to
  • Language
  • 35
  • 11
  • 5
  • 4
  • 3
  • 3
  • 3
  • 2
  • 1
  • 1
  • 1
  • 1
  • Tagged with
  • 97
  • 97
  • 32
  • 29
  • 19
  • 18
  • 18
  • 18
  • 17
  • 16
  • 15
  • 15
  • 15
  • 13
  • 12
  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
71

A Stated Preference Study for Assessing Public Acceptance Towards Autonomous Vehicles

Christos Gkartzonikas (5929697) 29 April 2020 (has links)
<div>Technology is rapidly transforming both vehicles and transportation systems. The nature of this transformation will depend on how fast the technology resulting from three related revolutions, those in automated, electric, and shared vehicles, will diffuse. At the same time, the ‘sharing’ economy is growing and affecting mobility in urban areas that includes additional travel alternatives, such as car-sharing services, ride-hailing services, bike-sharing services, and other micro-transit services. It is evident that to prepare for these large-scale operations involving autonomous vehicles (AVs), researchers and transportation professionals need the useful insights on people’s attitudes toward and on acceptance of AVs that can be gained through behavioral experiments. In addition to this, it is also important to understand how the deployment of AVs will impact vehicle ownership and mode choice decisions.</div><div><br></div><div>The goal of this dissertation is to assess the public acceptance of AVs and shared autonomous vehicles (SAVs) via a behavioral experiment (stated preference survey) and offer insights on the potential implications of AVs and SAVs on mode choices. The following four overarching research objectives were formulated: (a) identifying the factors influencing the behavioral intention to ride in AVs; (b) identifying the characteristics of the AV market segments; (c) evaluating the attributes impacting personal vehicle ownership decisions (i.e., decisions to postpone the purchase of a non-AV due to the emergence of AVs); and (d) assessing the factors affecting mode choice decisions after the emergence of autonomous ride-sharing services operated through AVs, and evaluating the corresponding value of travel time savings. The results of each part of the research framework are integrated in the last chapter of the dissertation in order to provide the final conclusions and recommendations of the study.</div><div><br></div><div>To achieve these research objectives, a survey of the general population was distributed online in a major urban area with an advanced multimodal transportation system and captive users of ride-sharing users (Chicago, Illinois) and in an urban area with a more automobile-oriented culture (Indianapolis, Indiana). The survey sample included 400 responses of adults, representative of age and gender on each area. </div><div><br></div><div>One of the contributions of this dissertation is a theoretical model to assess the behavioral intention to ride in AVs that includes components of the theory of Planned Behavior, the theory of Diffusion of Innovation and additional factors derived from the literature while evaluating possible interrelationships between these components. A more holistic approach along these lines can help explain whether the emerging AV technology can diffuse by identifying the factors and key determinants that influence the behavioral intention to ride in AVs. The market segmentation analysis can further provide knowledge of the socio-demographic characteristics of potential AV users and an accurate classification of these groups of potential users in terms of their willingness to ride in AVs. The findings can provide insights into perceptions of and attitudes toward AVs that can help transportation and urban planners, as well as original equipment manufacturers, to prepare for the deployment of AVs by designing marketing strategies to improve people’s perceptions of AVs and increase market penetration.</div><div><br></div><div>Moreover, this dissertation provides a well-documented and easy-to-use framework that can support both planning and policy decisions in urban areas in an era of emergent automated transportation technologies. In urban areas with advanced multimodal transportation networks, the framework can be applied to identify the impact attributes affecting shared mobility in urban settings. In urban areas with a more car-oriented culture, the framework can be applied to explore the potential impacts of the emergence of AVs on personal vehicle ownership patterns. Finally, the survey that was designed to fulfill the goal of this dissertation can be replicated and distributed in metropolitan areas outside the US with more advanced multimodal transportation systems or areas within the US with traditionally higher rates of affinity to innovativeness and areas where AVs have been pilot-tested in real-world road conditions.</div><div><br></div>
72

Variablen-Verdichtung und Clustern von Big Data – Wie lassen sich die Free-Floating-Carsharing-Nutzer typisieren?

Harz, Jonas 21 September 2016 (has links)
In den letzten Jahren hat die Verbreitung von stationsungebundenem Carsharing (Free- Floating-Carsharing) weltweit stark zugenommen. Aufgrund dessen wurden verschiedene Studien, welche die verkehrliche Wirkung von Free-Floating-Carsharing beschreiben, erstellt. Bisher unzureichend unter-sucht wurden jedoch die Nutzer von Free-Floating-Carsharing- Systemen. Im Rahmen der Mitarbeit der TU Dresden am Evaluationsbericht Carsharing in der Landeshauptstadt München standen für sämtliche Münchener Carsharinganbieter Daten zu Buchungen und Kunden zur Verfügung. Ziel dieser Arbeit war es nun, für die zwei Anbieter von Free-Floating-Carsharing eine Typisierung der Nutzer vorzunehmen. Für die Einteilung der Nutzer in Gruppen wurden zunächst Input-Variablen ausgewählt und erzeugt. Neben den zeitlichen Häufigkeiten der Nutzung für Monate, Wochentage und Zeitscheiben wurden zudem Gini-Faktoren berechnet, welche die Regelmäßigkeit der Nutzung abbilden. Außerdem wurden verschiedene Variablen aus den Buchungsdaten erzeugt. Dazu zählen Untersuchungen wie viele Fahrten amWohnort der Nutzer beginnen und/oder enden, ob Fahrten am gleichen Ort beginnen und enden und bei wie vielen Fahrten der Parktarif der Anbieter zum Einsatz kommt. Des Weiteren wurde untersucht, wie viele Fahrten den Flughafen als Start oder Ziel haben, wie der Einfluss des Wetters auf die Anzahl der Buchungen ist und wie hoch die mittlere Fahrtzeit pro Buchung je Nutzer ist. Alle Variablen dienten nun als Input für die Typisierung der Nutzer. Für die Typisierung wurde das Verfahren der Clusteranalyse ausgewählt. Dabei sind jedoch 30 Variablen eine zu große Anzahl, weswegen zuerst eine Verdichtung der Input-Variablen durchgeführt wurde. Dabei kam eine sogenannte Hauptkomponentenanalyse zum Einsatz. Diese bietet die Möglichkeit, verschieden stark korrelierende Variablen zusammenzufassen und dabei den Informationsgehalt dieser zu erhalten. Aus den 30 einfließenden Variablen ergaben sich mit Hilfe der Hauptkomponentenanalyse vier Faktoren, welche anschließend für die Clusteranalyse genutzt wurden. Jeder Nutzer lässt sich durch die vier Faktoren in einem vierdimensionalen Koordinatensystem ein-tragen. Anschließend kann in diesem Raum eine Clusterung durchgeführt werden. Für diese Arbeit wurde sich für das k-Means-Verfahren entschieden. Mit diesem wurden fünf Cluster bestimmt, welche die 13 000 Nutzer abbilden. Jeder Cluster lässt sich durch die Mittelwerte der eingeflossenen sowie durch soziodemografische Variablen wie Alter und Geschlecht und die Wohnorte der Nutzer hinsichtlich seiner Aussage interpretieren. Die fünf Cluster können in zwei Cluster mit einer niedrigen (Nr. 1 und 2), einen mit einer mittleren (Nr. 3) und zwei mit einer hohen Nutzungsintensität einteilen werden (Nr. 4 und 5). Cluster 1 vereint Nutzer, die selten aber spontane Fahrten unternehmen. Dabei sind überdurchschnittliche viele Fahrten am Wochenende und abends zu verzeichnen. In Cluster 2 finden sich Nutzer, die vorwiegend Fahrten mit langen Fahrtzeiten unternehmen. Dabei werden innerhalb einer Buchung mehrere Wege zurückgelegt, was sich an der hohen Nutzung des Parktarifs zeigt und daran, dass der größte Teil der Fahrten am Ausgangsort wieder enden. Diese Gruppe besitzt unter allen Gruppen einen überdurchschnittlich hohen Anteil an Frauen. Cluster 3 beschreibt den normalen Nutzer hinsichtlich der Nutzungsintensität und der zeitlichen Nutzung. Er ist mit 41,4% der Kunden der größte aller Cluster. Cluster 4 und 5 vereinen Kunden mit einer hohen Nutzungsintensität. Obwohl nur ca. 5% der Kunden in diesen beiden Gruppen zu finden sind, werden jedoch ein Drittel aller Fahrten von diesen Nutzern zurückgelegt. Cluster 4 beschreibt Nutzer mit einem typischen Pendlerverhalten. Dabei werden Fahrten vorwiegend Werktags und während der Hauptverkehrszeiten unternommen. Eine abnehmende Nutzung von Januar zu Juni lässt vermuten, dass andere Verkehrsmittel wie das Fahrrad genutzt werden. In Cluster 5 finden sich Kunden, die häufig Carsharing in der Nacht nutzen. Dies lässt vermuten, dass Aktivitäten des Nachtlebens besucht werden. Dieser Cluster hat im Vergleich zum Durchschnitt den geringsten Anteil an Frauen. Da die Ergebnisse ausschließlich auf den Anbieterdaten basieren, ist es nicht möglich, konkrete Aus-sagen über Effekte und Wirkungen von Free-Floating-Carsharing zu treffen und zu bewerten. Dafür wäre weitere Daten zum Beispiel aus Umfragen notwendig. Die klar abgrenzbaren und gut interpre-tierbaren Nutzergruppen zeigen jedoch, dass die gewählte Methodik sich zur Typisierung von Carsha-ringnutzern eignet. Eine Wiederholung des Verfahrens mit anderen Daten, zum Beispiel aus einem späteren Untersuchungszeitraum oder einer anderen Stadt, ist zu empfehlen.
73

A Systems-Level Approach to the Design, Evaluation, and Optimization of Electrified Transportation Networks Using Agent-Based Modeling

Willey, Landon Clark 16 June 2020 (has links)
Rising concerns related to the effects of traffic congestion have led to the search for alternative transportation solutions. Advances in battery technology have resulted in an increase of electric vehicles (EVs), which serve to reduce the impact of many of the negative consequences of congestion, including pollution and the cost of wasted fuel. Furthermore, the energy-efficiency and quiet operation of electric motors have made feasible concepts such as Urban Air Mobility (UAM), in which electric aircraft transport passengers in dense urban areas prone to severe traffic slowdowns. Electrified transportation may be the solution needed to combat urban gridlock, but many logistical questions related to the design and operation of the resultant transportation networks remain to be answered. This research begins by examining the near-term effects of EV charging networks. Stationary plug-in methods have been the traditional approach to recharge electric ground vehicles; however, dynamic charging technologies that can charge vehicles while they are in motion have recently been introduced that have the potential to eliminate the inconvenience of long charging wait times and the high cost of large batteries. Using an agent-based model verified with traffic data, different network designs incorporating these dynamic chargers are evaluated based on the predicted benefit to EV drivers. A genetic optimization is designed to optimally locate the chargers. Heavily-used highways are found to be much more effective than arterial roads as locations for these chargers, even when installation cost is taken into consideration. This work also explores the potential long-term effects of electrified transportation on urban congestion by examining the implementation of a UAM system. Interdependencies between potential electric air vehicle ranges and speeds are explored in conjunction with desired network structure and size in three different regions of the United States. A method is developed to take all these considerations into account, thus allowing for the creation of a network optimized for UAM operations when vehicle or topological constraints are present. Because the optimization problem is NP-hard, five heuristic algorithms are developed to find potential solutions with acceptable computation times, and are found to be within 10% of the optimal value for the test cases explored. The results from this exploration are used in a second agent-based transportation model that analyzes operational parameters associated with UAM networks, such as service strategy and dispatch frequency, in addition to the considerations associated with network design. General trends between the effectiveness of UAM networks and the various factors explored are identified and presented.
74

Elsparkcyklar : För ett integrerat transportnät / E-scooters : For an integrated transport network

Stålhammar, Emilia, Engberg, Markus January 2023 (has links)
Denna studie syftar till att belysa elsparkcykelns roll i transportplaneringen och arbetet med hållbara transportsystem. Mobilitet och tillgänglighet är faktorer som ligger till grund för människors val av resor och värderas därför högt inom städers transportplanering. Mikromobila fordon är innovativa transportmedel med syfte att främja hög mobilitet och tillgänglighet samtidigt som de bidrar med ett hållbart resande. Studien berör ämnet resebeteende för att undersöka användningen av mikromobilitet för alternativa transportmedel. Det har även gjorts undersökningar baserat på metoden mobility management för att undersöka metoder för beteendepåverkan samt vilka syfte dessa har. Meningen med dessa åtgärder ligger till grund i att minska bilanvändningen samt att människor ska övergå till mer hållbara transportmedel. Studien undersöker fenomenet elsparkcyklar och resebeteenden i Malmö stad, Helsingborg stad och Trelleborg kommun, några av Skånes största kommuner. Malmö och Helsingborg har implementerat elsparkcyklar i deras transportnät och ställer sig i grunden positiva till fordonen men att situationen på flera sätt behöver lösas. Politiken har uttalat sig om att elsparkcyklar är här för att stanna eftersom de ser en potential i att skapa en högre mobilitet och framtidstänk i dessa fordon. Regleringar för elsparkcyklar har tillkommit under senare år efter att fordonen implementerats. Detta på grund av att städerna var oförberedda när elsparkcykelföretagen valde att etablera sina verksamheter. Detta har medfört att städerna halkade efter i utvecklingen och processen att tillämpa regelverk har tillkommit i efterhand. Eftersom det är ett relativt nytt fordon har ingen större studie genomförts kring användningen av dessa fordon vilket har lett till att städer har haft svårt att analysera vilka verktyg som behövs för en bra utveckling av elsparkcyklar i staden. Studiens dokument- och intervjustudie har belyst kommunernas arbete med hållbara transporter och förändrat resebeteende samt deras syn på det nya mikromobila fordonet elsparkcykeln, vilket har bidragit till en bred grund att utveckla studiens analytiska del såväl som resultat. Uppsatsens slutsats kommer fram till att arbetet att uppnå ett hållbart resande kräver ett tillitsfullt samarbete mellan involverade transport- och statliga aktörer, samt tydligt utvecklade strategier för integrering av transportsystemen som underlättar för individer i påverkansarbetet. Men om elsparkcyklar är en del i detta är fortfarande oklart. / This study aims to shed light on the role of electric scooters in transport planning and sustainable transport systems. Mobility and accessibility are factors that underpin people's travel choices and are therefore highly valued in urban transport planning. Micromobile vehicles are innovative means of transportation with the aim of promoting high mobility and accessibility while contributing to sustainable travel. The study addresses the topic of travel behavior to investigate the use of micromobility for alternative means of transport. There have also been studies based on the mobility management methodology to investigate methods for influencing behavior and their purpose. The purpose of these measures is based on reducing car use and encouraging people to switch to more sustainable modes of transport. The study investigates the phenomenon of electric scooters and travel behavior in Malmö city, Helsingborg city and Trelleborg municipality, some of Skåne's largest municipalities. Malmö and Helsingborg have implemented electric scooters in their transport network and are basically positive about the vehicles, but the situation needs to be resolved in several ways. Politicians have stated that electric scooters are here to stay because they see a potential in creating higher mobility and future thinking in these vehicles. Regulations for electric scooters have been added in recent years after the implementation of the vehicles. This is because cities were unprepared when electric scooter companies chose to establish their operations. This has meant that cities have lagged behind in the development and the process of applying regulations has been added afterwards. Since it is a relatively new vehicle, no major study has been conducted on the use of these vehicles, which has led to cities having difficulty analyzing what tools are needed for a good development of electric scooters in the city. The study's document and interview study has highlighted the municipalities' work with sustainable transport and changed travel behavior as well as their view of the new micromobile vehicle the electric scooter, which has contributed to a broad basis for developing the study's analytical part as well as results. The thesis concludes that the work to achieve sustainable travel requires a trusting cooperation between the involved transport and governmental actors, as well as clearly developed strategies for integrating the transport systems that facilitate individuals in the advocacy work. But whether electric scooters are part of this is still unclear.
75

The Relationship between Socio-Demographic Constraints, Neighborhood Built Environment, and Travel Behavior: Three Empirical Essays

Kwon, Kihyun 09 December 2022 (has links)
No description available.
76

Nudging - ett nytt planeringsverktyg för hållbara resor? / Nudging - a new planning tool for sustainable travel?

Collander, Cristoffer, Johansson, Erika January 2018 (has links)
Hållbarhet har under de senaste decennierna blivit ett kraftfullt nyckelbegrepp som präglar trafikplaneringens riktlinjer. I kombination med de åtgärder som under många år använts för att öka andelen hållbara resor inom transportsektorn, såsom forskning om elbilar och alternativa bränslen, har på senare år även beteendepåverkande åtgärder implementerats under konceptet mobility management. En aktuell teori i sammanhanget är nudge-teorin, vilken innefattar hur beslutsfattare kan hjälpa människor att fatta bra beslut genom mindre åtgärder: genom att ge dem en knuff i rätt riktning, utan att kräva ekonomiska incitament eller begränsa människors valmöjligheter (Thaler och Sunstein 2008). Nudging som koncept är fortfarande relativt outforskat inom trafikplanering, även det finns vissa likheter med mobility management.   Syftet med denna studie är att öka förståelsen om konceptet nudging samt undersöka dess kvaliteter som planeringsverktyg för att påverka resebeteenden. Genom att studera fem kommuner som alla deltagit i det EU-finansierade projektet Knuffa resan rätt, undersöker uppsatsen hur nudge-åtgärder har använts samt hur användarna uppfattat att arbeta med verktyget. Uppsatsen ämnar också belysa hur de deltagande kommunerna tidigare arbetat med beteendepåverkande åtgärder och vilka skillnader de upplever med användandet av nudging som verktyg. Denna studie är en flerfallstudie, där intervjuer har använts som huvudmetod för att samla in empiriska data om de fem olika fallen som studien består av. I kombination med denna metod utfördes även en litteraturstudie, där relevant litteratur om hållbarhet och trafikplanering samlats in, samt ett teoretiskt ramverk om beteendevetenskap, där teorin om nudging lyfts fram.   Resultatet från fallstudierna visar att nudging ses som ett nytt spännande verktyg bland kommunerna, även om somliga påpekar att verktyget omedvetet tidigare använts. Skillnaden avser etableringen av nudging som begrepp, samt att kommunerna nu fått en förståelse för teorierna bakom nudging, hämtade från beteendeekonomin.  Dessa kunskaper har bidragit till en medvetenhet som kommer effektivisera, men också rättfärdiga, framtida beteendepåverkande projekt inom kommunerna. Däremot finns en problematik vad gäller arbetsprocessen vid nudge-åtgärder. I synnerhet krävs en mer omfattande utvärdering vilket resulterar i än mer resurskrävande projekt. Sannolikt kommer det krävas viss modifikation och flera omgångar av testprojekt innan ett bättre koncept eller modell har utvecklats som effektiviserar nudging som exklusivt planeringsverktyg. Tills dess bör insikterna om nudging användas främst som ett komplement till redan befintliga planeringsverktyg, med syftet att i stället effektivisera dessa.
77

Virtuell verklighet och resebeteende : En kvalitativ studie i flygresenärers inställning till virtuella resor

Boden, Ewa, Elhaddad, Reda January 2023 (has links)
Virtual reality, or VR, is a 3D technology that has become increasingly common, and in connection with the covid-19 pandemic, travel in VR was also launched. The purpose of our study is to shed light on the impact of virtual reality on Swedish air travelers’ travel behavior, by studying their attitude towards future air travel in relation to virtual travel. Can they choose virtual trips and there by forego the flight, or are travelers motivated after their virtual trips to also visit the destinations physically? Furthermore, how do they see the climate impact of aviation and whether it has any significance for them, we have conducted qualitative semi-structured studies where we collected sixteen responses from a survey posted in travel-interested groups on the social media platform Facebook and interviewed ten airtravelers at Stockholm Arlanda Airport. In addition, we interviewed an employee at a VR center and tested a game in virtual reality. We have analyzed our collected data material and compared the answers of all respondents. The results show that physical travel is important for most respondents, they mentioned various needs that they felt virtual travel could notsatisfy. The climate impact of the aviation industry had varying degrees of importance in the two compared respondent groups. The interest in virtual travel was not that great, but increased when a fictitious scenario was presented, when more people could imagine replacing the flight with the virtual one.
78

The Effects of Urban Form on Vehicle Emissions - Focusing On Urban Form Factors and Three Conventional Air Pollutions and Carbon Dioxide -

Lee, Jae Choon 20 December 2012 (has links)
No description available.
79

DYNAMICS OF SHARED MOBILITY SERVICES: USER DEMAND PATTERNS, CHARACTERISTICS, PERCEPTIONS, AND FUTURE INTENTIONS

Ricardo Chahine (19193095) 22 July 2024 (has links)
<p dir="ltr">This research evaluates shared mobility services in the United States, focusing on e-scooter sharing, bike-sharing, and ride-hailing in various urban settings. It aims to understand public and user perceptions, usage patterns, and the impact of urban design on these services. Key research questions include the differences in usage around campuses, public perceptions of shared mobility, future usage intentions post-COVID-19, and the influence of bike lane construction on shared mobility. The study uses survey data and various analytical methods to provide insights for policymakers and operators, introducing the CYCLES framework to enhance shared mobility systems and promote sustainable transportation solutions.</p>
80

Modeling framework for socioeconomic analysis of managed lanes

Khoeini, Sara 08 June 2015 (has links)
Managed lanes are a form of congestion pricing that use occupancy and toll payment requirements to utilize capacity more efficiently. How socio-spatial characteristics impact users’ travel behavior toward managed lanes is the main research question of this study. This research is a case study of the conversion of a High Occupancy Vehicle (HOV) lane to a High Occupancy Toll (HOT) lane, implemented in Atlanta I-85 on 2011. To minimize the cost and maximize the size of the collected data, an innovative and cost-effective modeling framework for socioeconomic analysis of managed lanes has been developed. Instead of surveys, this research is based on the observation of one and a half million license plates, matched to household locations, collected over a two-year study period. Purchased marketing data, which include detailed household socioeconomic characteristics, supplemented the household corridor usage information derived from license plate observations. Generalized linear models have been used to link users’ travel behavior to socioeconomic attributes. Furthermore, GIS raster analysis methods have been utilized to visualize and quantify the impact of the HOV-to-HOT conversion on the corridor commutershed. At the local level, this study conducted a comprehensive socio-spatial analysis of the Atlanta I-85 HOV to HOT conversion. At the general scale, this study enhances managed lanes’ travel demand models with respect to users’ characteristics and introduces a comprehensive modeling framework for the socioeconomic analysis of managed lanes. The methods developed through this research will inform future Traffic and Revenue Studies and help to better predict the socio-spatial characteristics of the target market.

Page generated in 0.0481 seconds