The value of non-working time is, in economic terms, a ratio of the marginal utility of time to the marginal utility of money, and hence is dependent on changes in income, changes in the opportunities for spending that income, changes in the amount of time disposable for leisure and changes in available leisure opportunities. A priori theorizing has yielded no conclusion on size or sign of the net effect on the value of time. Recent studies in the UK and The Netherlands suggest elasticities of VoT with respect to income of approximately 0.5. A study of the value of time in the UK in 1995 attempting to replicate an earlier study precisely also showed a result consistent with this value. However, given the limited evidence available, it is recommended that the value of time continue to be treated as increasing over time in proportion to GDP per capita unless there is local evidence to the contrary.
Recent studies show a wide distribution of individual time values for given income levels.
Slower modes might thus be expected to attract those with lower values of time and faster modes to attract those with higher values. Empirical evidence confirms this hypothesis. The highest value was double the lowest. Time savings for individuals attracted to an improved mode should be valued at the rate appropriate to the mode from which they are transferring. Recent studies of value of time savings for freight vehicles in the US, UK, Denmark, Sweden, Norway, Netherlands, France and Germany have been of two broad types.