Browsing by Author "Rizzi, Luis I."

Now showing 1 - 8 of 8
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    Estimating the Value of Risk Reduction for Pedestrians in the Road Environment: An Exploratory Analysis
    (ELSEVIER SCI LTD, 2011) Hensher, David A.; Rose, John M.; de Dios Ortuzar, Juan; Rizzi, Luis I.
    In recent years there has been a re-focus on the valuation of a statistical life from the ex post or human capital method to an ex ante willingness to pay (WTP) approach. This is in part a recognition that we need to focus on establishing the amount, ex ante, that individuals are willing to pay to reduce the risk of exposure to circumstances that might lead to death or degree of injury in the road environment. This study sets out a framework in which to identify the degree of preference heterogeneity in WTP of pedestrians to avoid being killed or injured. A stated choice experiment approach is developed. The empirical setting is a choice of walking route for a particular trip that a sample of pedestrians periodically undertakes in Australia. Mixed logit models are estimated to obtain the marginal (dis)utilities associated with each influence on the choice amongst the attribute packages offered in the stated choice scenarios. These conditional estimates are used to obtain the WTP distributions for fatality and classes of injury avoidance, which are then aggregated to obtain estimates for pedestrians of the value of risk reduction (VRR).
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    Estimating the willingness to pay and value of risk reduction for car occupants in the road environment
    (PERGAMON-ELSEVIER SCIENCE LTD, 2009) Hensher, David A.; Rose, John M.; de Dios Ortuzar, Juan; Rizzi, Luis I.
    In recent years there has been a re-focus on the valuation of a statistical life from the ex post or human capital method to an ex ante willingness to pay (WTP) approach. This is in part a recognition that we may have been undervaluing the cost of fatalities and injuries to society associated with crashes, but also a strong belief in the need to focus on establishing the amount, ex ante, that individuals are willing to pay to reduce the risk of exposure to circumstances that might lead to death or degree of injury on the road network. This study has developed a framework in which to identify the degree of preference heterogeneity in willingness to pay by individuals who are drivers or passengers in cars to avoid being killed or injured. A stated choice experiment approach is developed. The empirical setting is a choice of route for a particular trip that a sample of individuals periodically undertakes in Australia. The particular trip is described in enough detail to provide the respondent with a familiar market environment, providing all the relevant background information required for making a decision. Mixed logit models are estimated to obtain the marginal (dis)utilities associated with each influence on the choice amongst the attribute packages offered in the stated choice scenarios. These estimates are used to obtain the WTP distributions for fatality and injury avoidance, which are then aggregated to obtain estimates of the value of risk reduction (VRR), of which the fatality class is also known as the value of a statistical life (VSL). (C) 2009 Elsevier Ltd. All rights reserved.
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    Estimating the willingness-to-pay for road safety improvements
    (TAYLOR & FRANCIS LTD, 2006) Rizzi, Luis I.; Ortuzar, Juan de Dios
    The value of road safety is the fundamental input in social cost-benefit analysis of road safety schemes. It is also an increasingly important input in the social evaluation of almost any transport infrastructure project. This value is given by the amount that people are willing to pay for reducing the risk of a becoming a fatal victim or of suffering a serious injury. Traditionally, road safety willingness-to-pay has been estimated by means of contingent valuation and other surveys without making explicit reference to a particular travel demand context. The paper advocates the use of stated choice techniques that allow one to recreate the context of a particular trip customized to the respondent's past experience. For this and other reasons, it is argued that the proposed method is clearly superior to previous methods for estimating people's willingness-to-pay for improved road safety. The paper also provides a summary of the Chilean experience on road safety valuation using stated choice techniques; and it concludes by showing the importance of conducting local studies to elicit people's willingness to pay for safety.
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    Obtaining Public Transport Level-of-Service Measures Using In-Vehicle GPS Data and Freely Available GIS Web-Based Tools
    (2014) Arellana, Julian; Rizzi, Luis I.; Ortuzar Salas, Juan De Dios; Zuniga, Felipe
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    On the approximation bias to benefit measures in discrete choice models
    (IST EDITORIALI POLGRAFICI INT, 2008) Bowen, Cristian; Ortuzar, Juan de Dios; Rizzi, Luis I.
    We estimate the bias associated to using different approximations for calculating the benefits of transport projects. For this we generated a simulated databank that reproduces the real behaviour of a revealed preference sample on the choice of mode for work trips. Exact measures were computed for three transport policies differing in their degree of impact on mode choices. These values were then compared against the results of applying simpler but less precise measures, showing the existence of significant biases when classical explanatory models were considered. Significant biases were also detected when the correct methodology for marginal changes was applied in the presence of non-marginal policies. In the first case, the proportional error does not depend on the size of the policies, but in the second it grows with their impact. We also simulated another databank with non-linear utilities in income and calculated again some measures of welfare. We found that there are no significant biases if income effects are not considered. Neither did we find a systematic relation between these biases and the size (in terms of change) of the policy.
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    The impact of traffic images on travel time valuation in stated-preference choice experiments
    (TAYLOR & FRANCIS INC, 2012) Rizzi, Luis I.; Pablo Limonado, Juan; Steimetz, Seiji S. C.
    We develop a simple but modern stated-preference (SP) choice experiment to analyse the impact of traffic images on the estimated value of travel time savings (VTTS). A random subsample of survey respondents view computer-generated images that depict traffic conditions for congested and free-flow portions of hypothetical travel alternatives. The remaining respondents receive otherwise-identical surveys that only verbally describe the attributes of those alternatives. From surveys with images, the estimated VTTS is $7.40 per hour for congested travel time and $5.70 for free-flow travel time, implying a 'congestion premium' of 30%. From surveys without images, however, congested and free-flow VTTS estimates are identical at $5.90 per hour. Our results indicate that traffic images, however rudimentary, can substantially influence travel-time valuation, thus compelling further research on incorporating them into SP experimental design.
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    Valuing transport externalities
    (2015) Rizzi, Luis I.; Ortuzar Salas, Juan De Dios