Accessibility, a better quantification : logsums from the National Model System as accessibility measure. The National Model System is a disaggregate transport model, that predicts travel behaviour based on economic benefits (utilities). In this model, the Netherlands is divided into 1308 areas. When the destination choice, mode choice and time-of-day choice are modelled, the logsum, the average utility from a collection of possible choices with respect to destination and mode choice, will give a theoretical sound indication of accessibility of an area. Although they are used rarely in practice, logsums give a better indication of accessibility than travel time. A ‘forced’ change in mode choice, destination choice or time-of-day choice due to increased congestion, will have no, or even a positive effect on travel time, but does not have a positive effect on a persons perception. The change in mode, destination and time-of-day, however, will alter the logsums. Within the NMS, 490 persontypes are modelled, each with different travel behaviour. These personal differences affect the level of the logsum. When accessibility is measured in travel time, it will have the same value for all persons. Effects of policy measures can be evaluated with the NMS for different groups within the population when accessibility is based on logsums. (Author/publisher)
Abstract