The Distribution of Individual Values of Time: An Empirical Study Using Stated Preference Data

This paper reports the findings of further work undertaken on the Stated Preference (SP) data collected as part of the Department of Transport's Value of Time Project. The latter study estimated values of time in a variety of different circumstances and for a number of modes of travel and also examined how the value of time varied according to socio-economic factors. Although values of time were allowed to vary across individuals by segmenting the data according to socio-economic factors, the SP data permits the estimation of values of time at the individual level whereupon a distribution of individual values can be obtained.

The Department of Transport expressed some interest in what information could be provided by the SP data about the distribution of values of in-vehicle time across individuals. Individual values of in-vehicle time have been estimated for each of the five SP experiments which had previously been conducted to obtain a distribution for each survey context and also pooled across surveys to derive a population distribution. The problems of estimating values at the individual level with the SP data available are considered and the findings are compared with the average values previously derived in the Value of Time Study. How these individual values of time vary with socio-economic factors is also considered.