Alternative-specific constants are optional and can only be entered for the absolute calculation. They consist of utility components that can be entered at the nodes of the model structure - with the exception of at the lowest and the highest level - and can be included in the logsums, e.g.
.
Above the destination choice level, alternative-specific constants are vectors and therefore must be specified as zone attributes. From the destination choice level and below, they must be defined and entered as matrices. If the model structure does not include a destination choice level, then it is assumed that the destination choice has already been calculated. This means that alternative-specific constants must be specified as matrices.
