The Influence of Trip Length on Marginal Time and Money Values

An Alternative Explanation

Published in: The Expanding Sphere of Travel Behaviour Research: Selected Papers from the Proceedings of the 11th International Conference on Travel Behaviour Research / Kitamura, R., T. Yoshii, and T. Yamamoto, eds. (Bingley, United Kingdom: Emerald Group Publishing, 2009), 25 p

Posted on RAND.org on January 01, 2009

by Andrew Daly, Juan Carrasco

The objective of this work was to investigate whether heterogeneity in valuation existed in transport choice data and whether this heterogeneity might be responsible – through a range of mechanisms – for the observed increase in values of time with trip length. An analysis methodology was developed which allowed the estimation of choice models with error components representing heteroskedastic variation. The results of the analyses confirm that significant heterogeneity of preference exists in all the data sets analysed. This heterogeneity can be represented as heteroskedasticity in time or in cost and either is found to be significant in most of the models tested. The increase in value of time (VOT) with trip length is more likely to be due to heteroskedasticity (in the data studied) and the underlying VOT is therefore not increasing with distance at an individual level.

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