On the geometry of the consumer's surplus line integral

Consumer's surplus can be seen as a correct measure of the change in welfare under special conditions on the preferences of the consumer. The note addresses the question whether the intuitive appeal of the consumer''s surplus concept in the one-price change case extends into cases where several prices of inter-related goods change. An intuitively justified attribution of the change in welfare is conjectured. Sufficient conditions for this attribution to be exactly consistent with the geometry of the consumer''s surplus line integral are discussed.

Weighting methods in multi-attribute assessment of transport projects

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Transition choice probabilities in logit

We consider the widely used multinomial logit model with i.i.d. Gumbel random terms. Transition choice probabilities, i.e. probabilities of choosing alternative i in the first choice and alternative j in the second, are available in analytic form in the two extreme cases where the random terms of each alternative are independent or perfectly correlated across choices. We extend these results and provide the transition probabilities in analytic form in the case where the random terms follow a bi-extremal distribution with correlation coefficient varying in the full positive range between zero and one

Reference-Dependent Stochastic User Equilibrium with Endogenous Reference Points

We consider the application of reference-dependent consumer choice theory to traffic assignment on transportation networks. Route choice is modelled based on random utility maximisation with systematic utility embodying loss aversion for the travel time and money expenditure attributes. Stochastic user equilibrium models found in the literature have considered exogenously given reference points. The paper proposes a model where reference points are determined consistently with the equilibrium flows and travel times. The referencedependent stochastic user equilibrium (RDSUE) is defined as the condition where (i) no user can improve her utility by unilaterally changing path, (ii) each user has as reference point the current travel time and the money expenditure of one of the available paths, and (iii) if each user updates the reference point to her current path the observed path flows do not change. These conditions are formally equivalent to a multi-class stochastic equilibrium where each class is associated with a path and has as reference point the current state on the path, and the number of users in each class equals the current flow on the path. The RDSUE is formulated as a fixed point problem in the path flows. Existence of RDSUE is guaranteed under usual assumptions. A heuristic algorithm based on the method of successive averages is proposed to solve the problem. The model is illustrated by two numerical examples, one relates to a two-link network and another to the Nguyen-Dupuit network. A reference-dependent route choice model calibrated on stated preference data is used. The second example serves also to demonstrate the algorithm. The impact on the equilibrium of different assumptions on the degree of loss aversion with respect to the travel time attribute are investigated

Stochastic user equilibrium in the presence of state dependence

We consider the following two state-dependent effects at the level of route choice: inertia to change and, as a consequence of experience, lower perception variance for the currently used route. A heteroscedastic extreme value model embodying heterogeneity across alternatives in the mean of the random terms is used. Estimations based on stated preference data confirm the presence of both state-dependent effects. We introduce a new class of stochastic user equilibrium (SUE) models that take state-dependent effects into account. The class includes conventional SUE as special case. The equilibrium conditions are formulated as fixed-point states of deterministic day-to-day assignment processes. At the equilibrium (1) no user can improve her/his utility by unilaterally changing route, and (2) if each user shifts from her/his current route to her/his newly chosen route the observed route flows do not change. The existence of the equilibrium is guaranteed under usually satisfied conditions. A modified method of successive averages is proposed for solution. Examples related to a two arc network and to the Nguyen-Dupuis network illustrate the model

Decoupling Transport from Economic Growth

This paper reports on a research project that aimed to identify and assess measures which could be used to reduce travel demand while maintaining economic growth and enhancing environmental quality. The research methodology involved a detailed review of past research; contact with over 600 experts from around Europe and elsewhere for ideas on potential measures; detailed questionnaires from over 100 of these experts; and a series of three panel sessions held in different parts of Europe, each of which involved around 16 experts debating the merits of different measures and identifying case study evidence of their effectiveness. The end result was a shortlist of 13 measures, indicative of broad types, which are considered to be effective, and an indication of their effectiveness if applied across the European Union. Seven illustrative measures are discussed which stand out from the results as having proven potential (though not necessarily at a European scale) to influence transport intensity and/or unit environmental load whilst not having large detrimental effects on GDP. These are the areas where it is felt that European transport policy could most usefully be focussed in terms of decoupling of transport demand and economic growth

Urban Freight Transport Demand Modelling: a State of the Art

The paper provides a review of freight transport demand models for applications in urban and metropolitan areas. The perspective adopted is the short-term one of public decision-makers involved in transport planning and traffic management. The paper recalls the general methodology to be used for assessing the city logistics scenario and the features of models in relation to the planning horizons: strategic, tactical and operative. The focus is on the transport demand models able to support the assessment of short-term policies/measures. Several models and methods have been proposed. They usually refer to the multi-stage modelling approach and can be classified in terms of reference unit: truck/vehicle, commodity/quantity, delivery and mixed. The paper offers an analysis of pros and cons of each above classes of models. The research prospects are also identified

Users' preferences towards automated road public transport: results from European surveys

Abstract Collective automated road transport systems (ARTS) are the subject of current research in Europe. The paper reports on the results of the investigations about users' attitudes towards ARTS and conventional buses that have been carried out in twelve cities where the implementation of an ARTS service is being planned within the Citymobil2 project. A common stated preference questionnaire has been used. The econometric analysis has been based on the estimation of a logit model which has considered the choice for two alternatives: ARTS and minibus. The observed attributes are: waiting time, riding time and fare. Of particular interest, is the estimation of the alternative specific constant (ASC) of the ARTS, because this represents the mean of all the unobserved attributes of the automated system that affect the choice. With a common specification of the systematic utilities of ARTS and minibus, the observed attributes being the same, a positive value of the ASC is indicative of a relatively higher preference for the ARTS. The results show a relatively higher preference for ARTS across the cities where the ARTS is implemented inside a major facility. In other application contexts, commonalities in attitudes across cities are not found. The impacts on attitudes of the socio-economic attributes of the users are heterogeneous across cities

Using rail to make urban freight distribution more sustainable

Rail is today a minimally used modality in urban freight distribution. To reap the benefits of this more sustainable transport mode a few experiences in Europe have attempted to introduce innovative freight distribution schemes where rail is used. One of such schemes uses rail for the urban penetration leg. After having been consolidated in a centre located outside the urban area, goods are transported by shuttle trains to a centre located inside the central area (the multi-modal urban distribution centre – MUDC) and there are transferred to low-pollution road vehicles to reach their final destination. Other schemes use tramways. The paper provides a review of rail-based schemes which have been introduced in European cities. An in-depth assessment is provided of the scheme based on the use of a MUDC. The case study relates to the distribution of fish food in Rome. The environmental and energy benefits obtainable from the shift from the current road-only scheme to the MUDC scheme are estimated in physical and monetary units. An estimate is provided of the maximum public contribution that would still make the scheme beneficial for society as a whole, obtained as the difference between the social costs of the road-only scheme and those of the MUDC scheme. Also, an assessment is provided of the profitability of the scheme from the operators‟ viewpoint

Design of Passenger Interchanges

Three projects focussing on intermodality and interchanges are currently in progress, promoted by the European Commission: GUIDE, MIMIC and PIRATE. After a short description of each project, the paper concentrates on the MIMIC project. The MIMIC approach consists in a structured evaluation of the necessary and desirable conditions to improve interchanges and intermodality. In particular, the project s aim is to identify passengers needs and priorities in order to help decision makers to choose among the many investment projects competing for the same pot of money. MIMIC uses the notion of barriers to intermodality as a way of throwing light on and evaluating problems relating to interchanges in six sample cities (Bilbao, Copenhagen, London, Rome, Tampere and Warsaw). The tools used to assess and scale users needs are presented and commented. These include both surveying and modelling tools. The modelling tools (logit model, micro-simulation model and GIS tool) are described in detail. Finally, the most important barriers to intermodality are summarised and commented.Institute of Transport and Logistics Studies. Faculty of Economics and Business. The University of Sydne