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  • 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.
1

HOT Lane Policies and Their Implications

Goel, Rahul 2010 May 1900 (has links)
High-Occupancy toll (HOT) lanes allow lower-occupant vehicles (LOVs) to use a HOV lane for a fee, while maintaining free travel to qualifying HOVs. HOT lanes are gaining interest throughout the country as a strategy for meeting multiple performance objectives in congested urban freeway corridors. Currently there are ten fully operational HOT lanes around the country in seven different states and this research examined the nine of them (excluding I-35 W). Even with only a handful of operational HOT lane projects, there is great diversity in terms of HOT lane design and operations. With HOT lane implementation there are many issues, including: toll rates, vehicle occupancy requirement, number of access points, and safety. This research examined (i) the different factors which lead to the development of the HOT lanes in their respective corridors (ii) the objectives of the HOT lanes (iii) changes made in the corridor due to HOT lane implementation (iv) the different impacts of the HOT lanes and (v) the extent to which the objectives of the HOT lanes were achieved. Using three pairs of HOT lanes with similar design and operational characteristics, comparisons were made to examine the impacts of the similar HOT lanes in two different corridors. With the strict registration requirement for HOV3+ on the I-95 Express Lanes there were indications that some carpoolers broke up in to lower occupancy vehicles. Tolled access for HOV2s on I-95 as well as the SR 91 Express Lanes resulted in lower usage of the Express Lanes by the HOV2s (fewer than 30 percent of the total corridor HOV2s) as compared to a conventional HOV lane (60 percent) where HOV2 access is free. The effect of availability of transit on the HOT lanes can also be seen from SR 91 as compared to I-95. On SR 91, the Express bus does not use the Express Lanes and there was almost no change in its ridership after the Express Lanes were implemented. However, on I-95, the Express bus uses the Express Lanes and travel time of buses decreased by 17 minutes due to Express Lanes implementation. The Express bus ridership also increased by 30 percent. On the SR167 and I-25 HOT lanes, the exogenous factors like gas prices and economic recession seemed to influence the usage of the HOT lanes. In both the HOT Lanes, carpool usage was positively correlated to the gasoline prices. On I-25, the increasing unemployment rate coincided with the decreasing toll paying travelers. On SR 167 there were also indications of mode shifts among the transit, carpool and toll paying SOVs due to fluctuating gas prices. With declining gas prices, the transit and carpool usage went down while toll paying users increased. An inverse relationship between the convenience of access points and the safety perceived by the HOT lane users was found. For example, I-15 Express Lanes in Salt Lake City reduced the access points from unrestricted with the previous HOV lanes to limited with the Express Lanes. As a result, more predictable merging led to an increase in the perceived safety of the Express lanes as well as the speed of the corridor. On the other hand, some carpoolers mentioned not using the Express Lanes anymore because of access inconvenience. The access inconvenience was also mentioned by previous carpoolers in HOV lanes on I-95 as one of the reasons for not using the Express Lanes. These findings underscore the importance of outreach programs during the planning process of the HOT lanes to minimize the confusion among the previous users of the HOV lanes and spreading awareness among them regarding the increased safety benefits.
2

Modeling the Effect of New Commuter Bus Service on Demand and the Impact on GHG Emissions: Application to Greater Boston

Lyman, Christopher 02 July 2019 (has links)
The transportation sector is considered one of the major contributors to greenhouse gas (GHG) emissions in metropolitan areas, and any efforts to reduce these emissions requires strategic management of multiple transportation modes. This paper presents a method to identify opportunities to reduce GHG emissions by expanding commuter bus services and incentives to shift commuters from private cars to transit. The approach uses a nested multinomial logit model for mode choice in a region that includes driving alone, carpooling, walking, cycling, and using four possible transit modes (ferry, commuter rail, rapid transit and bus) by walk access or driving access. A model of existing conditions was calibrated with data from the Boston metropolitan area. Using an emission factor model based on average speeds from the California Air Resources Board (CARB), the net effect of new commuter bus service on GHG emissions from transportation was estimated. Potential GHG reductions are weighed against the capital and operating costs of new transit services to quantify the cost-effectiveness of a new commuter bus service for isolated origin-destination pairs. This modeling framework is used to optimize fares and bus frequency in order to identify the corridors with the most cost-effective potential for GHG reduction. Results are presented for the Boston region, demonstrating the feasibility of implementation and the potential magnitude of benefits for cost-effectively reducing GHG emissions associated with transportation. The method is general and can be applied in other cities around the world.
3

Nudging towards automobile- free living in Stockholm : An analysis of Stockholm's 2015 Green Parking Rates guideline and its impact on mode shift

Mečár, Matej January 2020 (has links)
This thesis explores the impact of the city of Stockholm􏰀s 2015 Green Parking Rates guideline on transportation mode shift. The guidelines were established in hopes of nudging occupants of newly built residential developments towards a mode shift and in so doing, towards car-light, car- free and more sustainable living. This nudging is facilitated through the utilization of positive mobility services such as the offering of bike-share and car-share services to residents, in hopes of reducing their need and desire for private automobiles. As a result of incorporating positive mobility services, the development community receives a reduction on the parking spaces they are obligated to construct, which come at a high economic cost to the individual property developers, those purchasing or renting their units as well as society as a whole. Consequently, the guidelines are a meant to be a tool to help the city of Stockholm reduce congestion and meet their newest sustainability goals. This thesis explores the perspectives of the development community as well as the planning departments at the city of Stockholm through the conducting of a policy analysis as well as through 16 semi structured interviews and explores some of the successes and challenges in establishing a mode shift. However, due to the short time period since the establishment of the guidelines, the city of Stockholm nor the development community have conducted a comprehensive evaluation to assess the guidelines􏰀 utility in facilitating a mode shift. The thesis suggests that a more collaborative process pre, during and after the development of projects would better serve Stockholm and its development community in achieving its sustainability goals.
4

What Moves You? : A Study of Mode Shift Motives in Stockholm / Vad rör dig? : En studie om förändringar i färdmedelsval i Stockholm

Gaio, Alexander January 2020 (has links)
What causes people to change their primary transportation mode and sustain the change in the absence of an incentive? Shifting towards sustainable modes is a vision shared by many municipal, regional, national and international bodies around the world, but it is difficult to change individuals’ behaviour, especially when there is no incentive to do so. Through understanding how individuals make decisions about their planned behaviour and determining what are opportune moments to re- learn travel habits, it may serve as a key opportunity to influence sustainable mode share. This study focuses on residential relocation to understand if the act of relocating serves as a catalyst to change transport behaviour. It further studies if car-lite developments under the Stockholm Green Parking Guidelines have impacted changes in travel behaviour towards more sustainable modes. By using surveys and interviews based on behavioural theory, it is possible to understand how individuals change their transport mode. The data collected also show how individuals may have a bias towards a particular transport mode and how policies can work to persuade them to choose another. The findings recommend measures to target programs for mode shift to the right people, at the right time to maximise effectiveness. They further recommend that proactive notification from information available in official databases can be used to implement this within the capabilities that currently exist in many jurisdictions. / Vad är det som får människor att ändra sitt primära transportsätt och upprätthålla förändringen trots avsaknad av incitament? Att övergå till mer hållbara transportsätt är en vision som delas av många kommunala, regionala, nationella och internationella organ runt om i världen men det är svårt att ändra individers beteende, särskilt när det inte finns något incitament till en förändring. Genom att förstå hur individer fattar beslut om sitt planerade beteende och att fastställa vilka tillfällen man som individ är mer öppen för att ta till sig nya resvanor, öppnas möjligheter för att påverka resvanor i en mer hållbar riktning. Denna studie fokuserar på individer som har bytt bostad, i syfte att förstå om flytten fungerar som en katalysator för ett förändrat transportbeteende. Den studerar vidare om utvecklingen mot ett minskat bilanvändande enligt riktlinjerna för Stockholms Gröna parkeringstal har skapat en förändring mot mer hållbara transportsätt. Genom att använda undersökningar och intervjuer baserade på beteendeteori är det möjligt att förstå hur individer ändrar sitt transportsätt. Uppgifterna som samlas in visar också hur individer kan ha en preferens för ett visst transportsätt och hur policyer kan arbeta för att övertyga dem att välja ett annat. Resultaten rekommenderar att man identifierar åtgärder för ett mer hållbart transportsätt och riktar in dessa till rätt personer vid rätt tidpunkt, i syfte att maximera effekten. De rekommenderar vidare att information tillgänglig i officiella databaser, och som är tillåten att användas inom dagens regelverk, kan användas för att implementera detta.
5

Études de type structure fonction du couplage électromécanique et de la coopérativité sous-unitaire chez les canaux potassiques dépendants du voltage

Haddad, Georges A. 05 1900 (has links)
Les canaux potassiques voltage-dépendants forment des tétramères dont chaque sous-unité comporte six segments transmembranaires (S1 à S6). Le pore, formé des segments S5-S6 de chaque sous-unité, est entouré de quatre domaines responsables de la sensibilité au potentiel membranaire, les senseurs de voltage (VS; S1-S4). Lors d’une dépolarisation membranaire, le mouvement des résidus chargés situés dans le VS entraine un mouvement de charges détectable en électrophysiologie, le courant de « gating ». L’activation du VS conduit à l'ouverture du pore, qui se traduit par un changement de conformation en C-terminal du segment S6. Pour élucider les principes qui sous-tendent le couplage électromécanique entre ces deux domaines, nous avons étudié deux régions présumées responsables du couplage chez les canaux de type Shaker K+, soit la région carboxy-terminale du segment S6 et le lien peptidique reliant les segments transmembranaire S4-S5 (S4-5L). Avec la technique du « cut-open voltage clamp fluorometry » (COVCF), nous avons pu déterminer que l’interaction inter-sous-unitaire RELY, formée par des acides aminés situés sur le lien S4-5L et S6 de deux sous-unités voisines, est impliquée dans le développement de la composante lente observée lors du retour des charges de « gating » vers leur état de repos, le « OFF-gating ». Nous avons observé que l’introduction de mutations dans la région RELY module la force de ces interactions moléculaires et élimine l’asymétrie observée dans les courants de « gating » de type sauvage. D’ailleurs, nous démontrons que ce couplage inter-sous-unitaire est responsable de la stabilisation du pore dans l’état ouvert. Nous avons également identifié une interaction intra-sous-unitaire entre les résidus I384 situé sur le lien S4-5L et F484 sur le segment S6 d’une même sous-unité. La déstabilisation de cette interaction hydrophobique découple complètement le mouvement des senseurs de voltage et l'ouverture du pore. Sans cette interaction, l’énergie nécessaire pour activer les VS est moindre en raison de l’absence du poids mécanique appliqué par le pore. De plus, l’abolition du couplage électromécanique élimine également le « mode shift », soit le déplacement de la dépendance au voltage des charges de transfert (QV) vers des potentiels hyperpolarisants. Ceci indique que le poids mécanique du pore imposé au VS entraine le « mode shift », en modulant la conformation intrinsèque du VS par un processus allostérique. / Voltage-gated potassium channels are tetramers and each subunit is formed of six transmembrane segments (S1 to S6). The pore, formed by the S5-S6 segments of each subunit, is surrounded by four modules responsible for sensitivity to the membrane potential, the voltage sensors (VS, S1-S4). During membrane depolarization, the movement of charged residues located in the VS causes a detectable charge movement called the gating current. The activation of the VS led to the opening of the pore, resulting in a conformational change in the C-terminal segment of S6. To elucidate the principles underlying the electromechanical coupling between these two domains, we examined two regions presumed responsible for the coupling among channels of the Shaker K + family: the carboxy-terminal region of S6 and the peptide bond linking the transmembrane segments S4-S5 (S4-5L). Using the cut-open voltage clamp fluorometry (COVCF), we have determined that the RELY inter-subunit interaction, formed by amino acids located on the S4-5L linker and S6 of two neighboring subunits, is involved in the development of the slow component observed during the return of the gating charges (OFF-gating) to their resting state. The introduction of mutations in the RELY region modulates the strength of these molecular interactions and eliminates the asymmetry observed in the wild type gating currents. Moreover, we demonstrate that this inter-subunit coupling is responsible for stabilizing the pore in the open state. We have also identified an intra-subunit interaction between residues I384 located on the S4-5L linker and F484 on the S6 segment of the same subunit. The destabilization of this hydrophobic interaction uncouples completely the movement of voltage sensors from pore opening. Without this interaction, the energy required to activate the VS is diminished due to the absence of mechanical weight applied by the pore. Furthermore, this uncoupling also eliminates the "mode shift", defined as an amplified shift of the voltage dependence of gating charge (QV) to hyperpolarizing potentials during prolonged depolarization, thus indicating that the mechanical load of the pore influences the entry of the VS into this shifted mode by modulating the conformation of the VS threw an intrinsic allosteric process.
6

Études de type structure fonction du couplage électromécanique et de la coopérativité sous-unitaire chez les canaux potassiques dépendants du voltage

Haddad, Georges A. 05 1900 (has links)
Les canaux potassiques voltage-dépendants forment des tétramères dont chaque sous-unité comporte six segments transmembranaires (S1 à S6). Le pore, formé des segments S5-S6 de chaque sous-unité, est entouré de quatre domaines responsables de la sensibilité au potentiel membranaire, les senseurs de voltage (VS; S1-S4). Lors d’une dépolarisation membranaire, le mouvement des résidus chargés situés dans le VS entraine un mouvement de charges détectable en électrophysiologie, le courant de « gating ». L’activation du VS conduit à l'ouverture du pore, qui se traduit par un changement de conformation en C-terminal du segment S6. Pour élucider les principes qui sous-tendent le couplage électromécanique entre ces deux domaines, nous avons étudié deux régions présumées responsables du couplage chez les canaux de type Shaker K+, soit la région carboxy-terminale du segment S6 et le lien peptidique reliant les segments transmembranaire S4-S5 (S4-5L). Avec la technique du « cut-open voltage clamp fluorometry » (COVCF), nous avons pu déterminer que l’interaction inter-sous-unitaire RELY, formée par des acides aminés situés sur le lien S4-5L et S6 de deux sous-unités voisines, est impliquée dans le développement de la composante lente observée lors du retour des charges de « gating » vers leur état de repos, le « OFF-gating ». Nous avons observé que l’introduction de mutations dans la région RELY module la force de ces interactions moléculaires et élimine l’asymétrie observée dans les courants de « gating » de type sauvage. D’ailleurs, nous démontrons que ce couplage inter-sous-unitaire est responsable de la stabilisation du pore dans l’état ouvert. Nous avons également identifié une interaction intra-sous-unitaire entre les résidus I384 situé sur le lien S4-5L et F484 sur le segment S6 d’une même sous-unité. La déstabilisation de cette interaction hydrophobique découple complètement le mouvement des senseurs de voltage et l'ouverture du pore. Sans cette interaction, l’énergie nécessaire pour activer les VS est moindre en raison de l’absence du poids mécanique appliqué par le pore. De plus, l’abolition du couplage électromécanique élimine également le « mode shift », soit le déplacement de la dépendance au voltage des charges de transfert (QV) vers des potentiels hyperpolarisants. Ceci indique que le poids mécanique du pore imposé au VS entraine le « mode shift », en modulant la conformation intrinsèque du VS par un processus allostérique. / Voltage-gated potassium channels are tetramers and each subunit is formed of six transmembrane segments (S1 to S6). The pore, formed by the S5-S6 segments of each subunit, is surrounded by four modules responsible for sensitivity to the membrane potential, the voltage sensors (VS, S1-S4). During membrane depolarization, the movement of charged residues located in the VS causes a detectable charge movement called the gating current. The activation of the VS led to the opening of the pore, resulting in a conformational change in the C-terminal segment of S6. To elucidate the principles underlying the electromechanical coupling between these two domains, we examined two regions presumed responsible for the coupling among channels of the Shaker K + family: the carboxy-terminal region of S6 and the peptide bond linking the transmembrane segments S4-S5 (S4-5L). Using the cut-open voltage clamp fluorometry (COVCF), we have determined that the RELY inter-subunit interaction, formed by amino acids located on the S4-5L linker and S6 of two neighboring subunits, is involved in the development of the slow component observed during the return of the gating charges (OFF-gating) to their resting state. The introduction of mutations in the RELY region modulates the strength of these molecular interactions and eliminates the asymmetry observed in the wild type gating currents. Moreover, we demonstrate that this inter-subunit coupling is responsible for stabilizing the pore in the open state. We have also identified an intra-subunit interaction between residues I384 located on the S4-5L linker and F484 on the S6 segment of the same subunit. The destabilization of this hydrophobic interaction uncouples completely the movement of voltage sensors from pore opening. Without this interaction, the energy required to activate the VS is diminished due to the absence of mechanical weight applied by the pore. Furthermore, this uncoupling also eliminates the "mode shift", defined as an amplified shift of the voltage dependence of gating charge (QV) to hyperpolarizing potentials during prolonged depolarization, thus indicating that the mechanical load of the pore influences the entry of the VS into this shifted mode by modulating the conformation of the VS threw an intrinsic allosteric process.
7

Development of a Logit model of the transition effect to public transport

Ziedén, Therése January 2017 (has links)
The importance of traffic planning has, throughout the years, been in- creased, providing sustainable developments of traffic and infrastructural investments. The analysis of the current traffic situation and the evalua- tion of the effects of a future investment are crucial for the socio-economic benefits maintenance. These analyses and evaluations are most commonly done using traffic simulation models. One of the main traffic planning aims, nowadays, is to increase the number of public transport users against the number of private car users. This change in mode choice is called transition effect and could be beneficial both from an environmental and socio-economic perspective. This thesis aims to evaluate and improve the macroscopic traffic demand and transition model, used fot the city of Norrköping. Additionally, the thesis investigates if a general transition Logit model can be developed and which parameters are the most important to be included in a modal choice estimation. For the needs of this study, the traffic planning software Visum is used. The travel mode distribution is calculated by Logit models coded in Python-scripts integrated in Visum. Then, a traffic assignment is performed by Visum, computing new travel times as inputs to the Logit model and this iterative procedure continues until the system reaches an equilibrium. The thesis aims for a more reliable prediction of the transition effect by correcting the Python-scripts and estimating the parameters of the Logit model using data from surveys. The study shows that travel times is the most important factor for realistic results generation. However, the data used for the estimation of the Logit model parameters did not include sufficient information of travel times. The travel times had to be calculated, using two different methods, in order to be included in the estimation of new parameters. Although these methods could not provide any positive effects on the transition, they did prove the importance and significance travel time have when developing a traffic model. The result of the study invokes the importance to further develop the method of calculating travel times, when the input data is not sufficient, and shows that the travel time parameters are case specific.
8

On the electrification of road transportation – A review of the environmental, economic, and social performance of electric two-wheelers

Weiss, Martin, Dekker, Peter, Moro, Alberto, Scholz, Harald, Patel, Martin K. 11 November 2020 (has links)
Electrification is widely considered as a viable strategy for reducing the oil dependency and environmental impacts of road transportation. In pursuit of this strategy, most attention has been paid to electric cars. However, substantial, yet untapped, potentials could be realized in urban areas through the large-scale introduction of electric two-wheelers. Here, we review the environmental, economic, and social performance of electric two-wheelers, demonstrating that these are generally more energy efficient and less polluting than conventionally-powered motor vehicles. Electric two-wheelers tend to decrease exposure to pollution as their environmental impacts largely result from vehicle production and electricity generation outside of urban areas. Our analysis suggests that the price of e-bikes has been decreasing at a learning rate of 8%. Despite price differentials of 5000 ± 1800 EUR2012 kW h−1 in Europe, e-bikes are penetrating the market because they appear to offer an apparent additional use value relative to bicycles. Mid-size and large electric two-wheelers do not offer such an additional use value compared to their conventional counterparts and constitute niche products at price differentials of 700 ± 360 EUR2012 kW−1 and 160 ± 90 EUR2012 kW−1, respectively. The large-scale adoption of electric two-wheelers can reduce traffic noise and road congestion but may necessitate adaptations of urban infrastructure and safety regulations. A case-specific assessment as part of an integrated urban mobility planning that accounts, e.g., for the local electricity mix, infrastructure characteristics, and mode-shift behavior, should be conducted before drawing conclusions about the sustainability impacts of electric two-wheelers.
9

Benchmarking a Transit System on Time-Constrained Trip Chain Access: A Comparative GIS Analysis of Two University Towns

Lachman, Michael A. 15 June 2017 (has links)
No description available.
10

Das E-Lastenrad als Alternative im städtischen Wirtschaftsverkehr. Determinanten der Nutzung eines „neuen alten“ Fahrzeugkonzepts

Gruber, Johannes 05 March 2021 (has links)
Elektrifizierte Lastenfahrräder werden als ein Lösungsansatz für die wachsenden Herausforderungen des städtischen Wirtschaftsverkehrs gesehen. Fokus dieser Arbeit ist eine Abschätzung des Einsatzpotenzials dieses Fahrzeugkonzepts unter Betrachtung von konzeptionellen, verkehrlichen und wirtschaftlichen Aspekten. Als kumulative Dissertation enthält sie fünf Fachartikel, gruppiert zu drei Forschungsbeiträgen. Im ersten Forschungsbeitrag wird erörtert, wie erfolgversprechend das E-Lastenrad, eine Neuauflage des alten Konzepts Lastenfahrrad, in einem Markt mit ersten Anwendern (Kurierdienstleistung) ist. Die Auftragsstruktur im Stadtkuriergeschäft bietet ein substanzielles Marktpotenzial für E-Lastenräder, allerdings erschwert die Positionierung zwischen zwei etablierten Modi (Pkw und Fahrrad) den Markteintritt. Der zweite Teil der Analyse weitet den Blick auf alle Branchen und bietet eine strukturierte Beschreibung der verschiedenartigen Einflussfaktoren (Treiber und Hemmnisse), die auf die Lastenradnutzung im städtischen Wirtschaftsverkehr wirken. Als relevante Entscheidungskriterien konnten identifiziert werden: fahrzeugseitige Aspekte, Strukturen und Prozesse des adoptierenden Unternehmens, Einstellungen der Entscheider*innen, weiche Faktoren sowie regulative und räumliche Rahmenbedingungen. Der dritte Beitrag thematisiert die operative Eignung des E-Lastenrads, indem seine Fahrtzeiten einem Pkw gegenübergestellt werden. Bei Strecken bis zu 3 km sind beide Modi nahezu gleich schnell. Die Hälfte aller Fahrten bis 20 km Distanz würde bei einem Wechsel vom Pkw zum Lastenrad höchstens 2–10 min länger dauern (ohne Berücksichtigung der Parksuchzeit). Bereits kleine Änderungen an den Verkehrsbedingungen könnten noch bestehende Vorteile des Pkw spürbar verringern. Insgesamt erweitert die Arbeit maßgeblich das Wissen zu einem „neuen alten“ Fahrzeugkonzept, dem ein Potenzial zur Auflösung von bislang auf das Automobil hin ausgerichteten Systemen beigemessen wird. / Shifting trips to electric cargo bikes is one possible solution to deal with the growing challenges of urban commercial transport. This thesis combines conceptual, transport-related, and economic aspects as a foundation to assess the feasibility of this vehicle concept for freight and service trips. It contains five scientific papers, which provide three research contributions. The first contribution identifies the potentials of electric cargo bikes among first users (i.e., courier logistics services). Electric cargo bikes are an updated and re-envisioned version of freight bicycles. The features of point-to-point courier logistics assignments offer a substantial market opportunity for electric cargo bikes. However, being positioned between two established modes (i.e., car and bicycle) handicaps the market entry of cargo bikes. For the second contribution, the scope was widened to include all business sectors. A structured description is presented of the various determinants (i.e., drivers and barriers) affecting commercial cargo bike use. Among these were vehicle-specific factors, structures and practices of the company, attitudes of decision-makers, soft factors, regulatory frameworks, and spatial conditions. The third contribution explores the travel time differences between electric cargo bikes and cars for commercial trips. For trip distances of up to 3 kilometers, the travel times of both modes largely overlap. Half of all trips up to 20 kilometers would take only a maximum of 2 to 10 minutes longer by electric cargo bike (excluding the additional time for finding a parking spot). Small modifications in traffic could have considerable effects in reducing the current travel time advantages of cars. Consequently, this dissertation contributes towards the state-of-research by expanding the scientific knowledge of a type of vehicle that has the potential to disrupt car-dependent transportation systems.

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