01044002

Component

Researchers are increasingly making use of random coefficients structures, such as Mixed Logit, in the analysis of air travel choice behavior. These models have the advantage of being able to retrieve random variations in sensitivities across travelers, leading to very significant gains in modeling accuracy. However, an important issue arises in the computation of willingness to pay indicators, such as the valuation of travel time savings (VTTS), on the basis of randomly distributed coefficients. Indeed, with the standard approach of using simulation of the ratios across random draws, major problems can be caused by outliers, leading to biased trade-offs, which in turn lead to major issues in policy analyses. In this paper, we explore a different approach, making use of individual-specific draws from the random distributions, conditioned on the observed sequence of choices for each respondent. An analysis making use of Stated Preference data for airport and airline choice confirms the advantages of the approach using conditional draws, producing much more realistic distributional patterns for a range of willingness to pay indicators, including but not limited to the VTTS. Finally, the analysis also reveals important differences between the trade-offs obtained with the MNL and MMNL models.

01042056

07-0165

English

22p

2007

Transportation Research Board 86th Annual Meeting

CD-ROM

Figures (5) ; References; Tables (8)

Air traffic; Air transportation; Air travel; Behavior; Choice models; Random variables; Randomization; Route choice; Stochastic processes; Travel behavior; Travel time; Value of time

Choices; Mixed logit models; Time savings; Willingness to pay

Aviation; Data and Information Technology; Passenger Transportation

Transportation Research Board Annual Meeting 2007 Paper #07-0165

TRIS, TRB

Feb 8 2007 4:44PM