In "Values of travel time in Europe: Review and meta-analysis" Wardman, Chintakayala and de Jong (2016) distinguish between mode used and mode valued. Some thoughts/questions on this.
As the authors write: "Mode used here relates to the characteristics of the travellers, with income being a key differentiator, and mode valued relates to the intrinsic features of the mode itself. " This distinction seems highly relevant to me.
For instance, "due to self-selection relating in part to income differences, car users have higher values than train users who in turn have higher values than bus users”. But, as far as I see it, this does not imply much about a given person's prior evaluation of the value of time in different modes. A person with a high income will have a higher VOT of transport than a person with a low income whatever the modal choice.
Now, you may argue (but even that seems disputable to me) that for cost-benefit analysis, it is the ex post value that matters. But what if your objective is to model mode choice? Ex ante, the sorting of the mode choice according to income has not yet taken place. Can we then use the value of time taken from surveys that estimate the VOT from the trade-offs people make within a mode? Shouldn't we use the "mode valued" to model mode choice?
apart from the income level, "perception of safety" level of adventoursomeness", " reflections to early life experiences can be intervening variables for value of mode and choice of mode.
Laurent, I understand the Wardman et al. argument that people value travel time according to the mode they choose and/or can afford.
Now, I find your formulation of the question in 4th paragraph a bit confusing. Care to rephrase?