Browsing by Author "Ortuzar, Juan De Dios"

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    Implications of thresholds in discrete choice modelling
    (TAYLOR & FRANCIS LTD, 2006) Cantillo, Victor; Ortuzar, Juan De Dios
    Individual choices are affected by complex factors and the challenge consists of how to incorporate these factors in order to improve the realism of the modelling work. The presence of limits, cut-offs or thresholds in the perception and appraisal of both attributes and alternatives is part of the complexity inherent to choice-making behaviour. The paper considers the existence of thresholds in three contexts: inertia (habit or reluctance to change), minimum perceptible changes in attribute values, and as a mechanism for accepting or rejecting alternatives. It discusses the more relevant approaches in modelling these types of thresholds and analyses their implications in model estimation and forecasting using both synthetic and real databanks. It is clear from the analysis that if thresholds exist but are not considered, the estimated models will be biased and may produce significant errors in prediction. Fortunately, there are practical methods to attack this problem and some are demonstrated.
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    Understanding suburban travel demand: Flexible modelling with revealed and stated choice data
    (PERGAMON-ELSEVIER SCIENCE LTD, 2007) Espino, Raquel; Ortuzar, Juan De Dios; Roman, Concepcion
    We analyse the choice of mode in suburban corridors using nested logit specifications with revealed and stated preference data. The latter were obtained from a choice experiment between car and bus, which allowed for interactions among the main policy variables: travel cost, travel time and frequency. The experiment also included parking cost and comfort attributes. The attribute levels in the experiment were adapted to travellers' experience using their revealed preference information. Different model specifications were tested accounting for the presence of income effect, systematic taste variation, and incorporating the effect of latent variables. We also derived willingness-to-pay measures, such as the subjective value of time, that vary among individuals as well as elasticity values. Finally, we analysed the demand response to various policy scenarios that favour public transport use by considering improvements in level-of-service, fare reductions and/or increases in parking costs. In general, demand was shown to be more sensitive to policies that penalise the private car than those improving public transport. (c) 2007 Elsevier Ltd. All rights reserved.