84 research outputs found
Elbilpolitikk fra et samfunnsøkonomisk perspektiv
This thesis focuses on the economics and polices for the electrification of transport. Over the last few years we have observed a rapid rise in the number of battery electric vehicles (BEVs) in Norway. This growth is the combined result of rapid technological change and a targeted national climate policy. The rising share of BEVs relative to the share of
conventional vehicles could lead to socio-economic benefits such as reduced greenhouse gas emissions and local pollution, but it could also pose new challenges such as pressure on the capacity of the electricity distribution network. In addition, BEVs have similar negative externalities as fossil-fueled vehicles with regards to congestion, road wear and accidents. BEVs can mitigate some market failures and exacerbate others, creating a messy optimization problem for the social planner. This illustrates the need for new knowledge on mechanisms and welfare enhancing policies in the transport and electricity markets as they become more integrated. This thesis seeks to contribute to the body of knowledge on the subject, in the following introductory chapter and four independent chapters. The latter chapters are written as scientific papers that are either published or in the process of getting published in peer-reviewed journals.Denne avhandlingen tar for seg elbilpolitikk i et samfunnsøkonomisk perspektiv. De siste årene har vi opplevd en rask økning i antall elbiler i Norge. Denne veksten er et resultat av både rask teknologisk utvikling og en målrettet nasjonal klimapolitikk. Den økende andelen av elbiler i forhold til andelen konvensjonelle biler kan føre til samfunnsøkonomiske fordeler som reduserte klimagassutslipp og lokal forurensning, men det kan også gi nye
utfordringer som press på kapasiteten til strømdistribusjonsnettet. I tillegg har elbiler tilsvarende eksterne kostnader som konvensjonelle biler med tanke på kø, veislitasje og ulykker. Elbiler kan dempe noen markedssvikt og forverre andre, og skape et rotete optimaliseringsproblem for samfunnsplanleggeren. Dette understreker behovet for ny kunnskap om den gjensidige påvirkningen mellom transport- og elektrisitetsmarkedet, og hva som kan være samfunnsmessig effektiv politikk. Denne avhandlingen bidrar til kunnskapen om emnet, i det følgende kappen og fire uavhengige kapitler. De siste kapitlene er skrevet som vitenskapelige artikler som enten er publisert eller i ferd med å bli publisert i fagfellevurderte tidsskrifter
Computing Optimal Tolls with Arc Restrictions and Heterogeneous Players
The problem of computing optimal network tolls that induce a Nash equilibrium of minimum total cost has been studied intensively in the literature, but mostly under the assumption that these tolls are unrestricted. Here we consider this problem under the more realistic assumption that the tolls have to respect some given upper bound restrictions on the arcs. The problem of taxing subnetworks optimally constitutes an important special case of this problem. We study the restricted network toll problem for both non-atomic and atomic (unweighted and weighted) players; our studies are the first that also incorporate heterogeneous players, i.e., players with different sensitivities to tolls.
For non-atomic and heterogeneous players, we prove that the problem is NP-hard even for single-commodity networks and affine latency functions. We therefore focus on parallel-arc networks and give an algorithm for optimally taxing subnetworks with affine latency functions. For weighted atomic players, the problem is NP-hard already for parallel-arc networks and linear latency functions, even if players are homogeneous. In contrast, for unweighted atomic and homogeneous players, we develop an algorithm to compute optimal restricted tolls for parallel-arc networks and arbitrary (standard) latency functions. Similarly, for unweighted atomic and heterogeneous players, we derive an algorithm for optimally taxing subnetworks for parallel-arc networks and arbitrary (standard) latency functions.
The key to most of our results is to derive (combinatorial) characterizations of flows that are inducible by restricted tolls. These characterizations might be of independent interest
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Dynamic congestion pricing in within-day and day-to-day network equilibrium models
This dissertation explores two kinds of dynamic pricing models which react to within-day and day-to-day variation in traffic. Traffic patterns vary within each day due to uncertainty in the supply-side that is caused by non-recurring sources of congestion such as incidents, poor weather, and temporary bottlenecks. On the other hand, significant day-to-day variations in traffic patterns also arise from stochastic route choices of travelers who are not fully rational. Using slightly different assumptions, we analyze the network performance in these two scenarios and demonstrate the advantages of dynamic pricing over static tolls. In both cases, traffic networks are characterized by a set of stochastic states. We seek optimal tolls that are a function of the network states which evolve within each day or across days.
In the within-day equilibrium models, travelers are assumed to be completely rational and have knowledge of stochastic link-states, which have different delay functions. At every node, travelers observe the link-states of downstream links and select the next node to minimize their expected travel times. Collectively, such behavior leads to an equilibrium, which is also referred to as user equilibrium with recourse, in which all used routing policies have equal and minimal expected travel time. In this dissertation, we improve the system performance of the equilibrium flows using state-dependent marginal link tolls. These tolls address externalities associated with non-recurring congestion just as static marginal tolls in regular traffic assignment reflect externalities related to recurring congestion.
The set of tolls that improve system performance are not necessarily unique. Hence, in order to make the concept of tolling more acceptable to the public, we explore alternate pricing mechanisms that optimize social welfare and also collect the least amount of revenue in expectation. This minimum revenue toll model is formulated as a linear program whose inputs are derived from the solution to a novel reformulation of the user equilibrium with recourse problem.
We also study day-to-day dynamic models which unlike traditional equilibrium approaches capture the fluctuations or stochasticity in traffic due to route choice uncertainty. Travelers decisions are modeled using route choice dynamics, such as the logit choice protocol, that depend on historic network conditions. The evolution of the system is modeled as a stochastic process and its steady state is used to characterize the network performance. The objective of pricing in this context is to set dynamic tolls that depend on the state of the network on previous day(s) such that the expected total system travel time is minimized. This problem is formulated as an average cost Markov decision process. Approximation methods are suggested to improve computational tractability.
The day-to-day pricing models are extended to instances in which closed form dynamics are unavailable or unfit to represent travelers' choices. In such cases, we apply Q-learning in which the route choices may be simulated off-line or can be observed through experimentation in an online setting. The off-line methods were found to be promising and can be used in conjunction with complex discrete choice models that predict travel behavior with greater accuracy.
Overall, the findings in this dissertation highlight the pitfalls of using static tolls in the presence of different types of stochasticity and make a strong case for employing dynamic state-dependent tolls to improve system efficiency.Civil, Architectural, and Environmental Engineerin
Congestion pricing and long term urban form: Application to Ile-de-France
We propose an efficient algorithm that solves the monocentric city model with traffic congestion, and use it to explore the impact of congestion pricing on urban forms and, hence, on transport volume, CO2 emissions and energy consumption. The application focuses on the region Ie-de-France. Four pricing policies are considered: no toll, where transport cost is equal to the vehicle operating cost, cordon toll where users pay the toll when they drive inside cordon region linear toll (optimal under the class of linear tolls) and optimal toll (or first-best toll). The linear toll is equivalent to an increase in the vehicle operating cost. It performs well with respect to the first-best solution but, since it applies identically to all trips, it is not likely to be relevant in practice. By comparison to the no-toll situation, optimal congestion pricing reduces the radius of the city and the average travel distance by 34% and 15%, respectively.Nous proposons un algorithme de résolution du modèle monocentrique de transport avec congestion. Nous utilisons cet algorithme afin d'explorer l'impact de différents schémas de tarification de la congestion sur la forme urbaine, et par conséquent, sur les véhiculeskilomètres (émissions de CO2) à long terme. L'application empirique concerne la région Îlede- France. Quatre régimes de tarification sont considérés : (i) absence de tarification, où une taxe linéaire reflète le coût d'usage du véhicule ; (ii) péage cordon, où les voitures payent pour passer à l'intérieur d'une zone donnée ; (iii) taxe linéaire optimale, proportionnelle à la distance parcourue (optimale dans la classe des taxes linéaires) ; et (iv) taxe optimale (optimum de premier rang). Par rapport à (i), la taxe optimale aboutit à des réductions de 34% et 15%, respectivement pour le rayon de la ville et la distance parcourue moyenne
Cooperatives and irrigation in Vietnam
Cooperative agricultural activity has existed in Vietnam in various forms for many decades. Under central planning, cooperative institutions provided a means for the government to extract surplus from agriculture for the development of the industrial sector. Now, under policies promoting market liberalization in agriculture, household farming units are no longer obliged to transact with the cooperative. The focus of this dissertation is on the interaction between autonomous household production units and cooperative institutions;Collective action around irrigation represents one economic motive for coop participation. Recent developments in club theory provide a conceptual framework within which analysis can be conducted. The (partially) non-rival and excludable characteristics of irrigation satisfy the requirement of the model while the presence of agricultural cooperatives suggests a possible means for organizing household production units for efficient utilization of irrigation. A household production model is employed to address the external effects of irrigation among households. The conditions of Pareto optimality for the hybrid model, which combines club theory and household production theory, are derived and compared with the corresponding conditions of conventional club models. The comparative statics of the model are exploited to derive labor market consequences of a shared partially non-rival good;An empirical analysis is conducted using data from The Living Standards Measurement Survey--an elaborate household and community questionnaire which contains substantial data on household use of irrigation and participation in cooperatives. Evidence is reported for model predictions regarding coop formation, coop participation and labor market effects. The appropriateness of the model confirmed the viability of state cooperatives in a liberalized economy and confirmed the gains in labor productivity due to irrigation infrastructure
LKW-Maut für die Umwelt?
LKW-MAUT FÜR DIE UMWELT?
LKW-Maut für die Umwelt? / Greil, Franz [Hrsg.] (Rights reserved) ( -
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