Dr. Matthieu de Lapparent

INRETS, France

March 31, 2008, 14:15, Room MA A3 30 (click here for the map)

Modeling the value of time

There is a plenty of literature on the topic of the value of travel time savings (VTTS) that covers both its theoretical and empirical dimensions. It is a key concept in transport analysis as it is used in assessment of user costs and benefits from a modification of transport infrastructure (traffic capacities, new modes of transport, etc.). Modelling and estimating realistic and reliable willingnesses to pay for saving travel time is therefore of utmost importance to make appropriate planning decisions. The outline of the presentation is as follows. In a first step, the theoretical framework of time allocation subject to budget, time, technological, space, and production constraints is presented. It is adapted from the original analysis frameworks of Becker(1965) and de Serpa(1971). Definition of the VTTS is derived from it. Its properties with respect to travel attributes and characteristics of the traveller are then discussed. The second part of the presentation turns to econometric modelling of the VTTS. It proposes flexible functional forms that take into account stylized facts and theoretical results. Estimation of various discrete choice models is made in a third step with Biogeme by using data from the 2001 Swissmetro SP survey. The results show that non linear utility functions in the presence of both deterministic and unobserved heterogeneity of tastes perform better than conventional approaches. Conclusion of the presentation discusses extensions and future research tracks. <ul class='text'> <li> Becker, G.S. (1965), A theory of the allocation of time, The Economic Journal, Vol. 75 (299), pp. 493-517</li> <li> Ben-Akiva, M., and S. Lerman (1985), Discrete Choice Analysis: Theory and - Application to Travel Demand, the MIT Press</li> <li> Bierlaire, M. (2003), BIOGEME: A free package for the estimation of discrete choice models , Proceedings of the 3rd Swiss Transportation Research Conference, Ascona, Switzerland.</li> <li> Lapparent, M.(de), de Palma, A. and C. Fontan, Nonlinearities in the valuation of travel attributes, Proceedings of the Professional Transportation Research Conference, 2002, Cambridge, UK.</li> <li> Daly, A. and Bierlaire, M. (2006), A General and Operational Representation of Generalised Extreme Value Models,Transportation Research Part B 40(4), 285-305</li> <li>De Serpa, A. C. (1971), A theory of the economics of time, The Economic Journal, 81 (321),. 828-846</li> <li> Hess, S., Bierlaire, M. and Polak, J. (2005), Estimation of value of travel-time savings using Mixed Logit models, Transportation Research Part A, 39(3), 221-236</li> <li> Train, K. (2003), Discrete choice with simulation, Cambridge University Press</li> <li> Truong, T.P and D.A. Hensher (1987), Measurement of Travel Time Values and Opportunity Cost from a Discrete-Choice Model, Economic Journal, vol. 95(378), 438-51 </li> </ul>

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