An aggregate measure of travel utility

The paper examines the effect of separating the total utility associated with a choice into components associated with the choice itself and with the transaction or travel involved in realising the choice. It derives an aggregate measure of transaction utility based on the logit model of choice and an interpretation is given in terms of random utility theory. The main interest lies in exploring aggregate measures of the transaction utility, since these can be used to generate costs for an aggregate model which will be consistent with the parent disaggregate model and can also be used to form the basis of such summary measures of travel as accessibility indices. Finally, the transaction component is used to identify the travel component of a consumers' surplus measure of benefit and thus enable the consumers' surplus to be disaggregated into travel and locational benefits.