Transit Fares can be represented in numerous ways and are highly-dependent upon the commercial modeling system that is used. Fares can be represented as a flat fare, transfer discounts, Some systems can accurately represent all transfer combinations while others this has to be approximated.
# Fare discounts and approximations
Sometimes when certain fare discounts are very prevalent, a modeler may choose to represent the average fare paid as the modeled fare. This can be approximated by dividing the total fare revenue for an agency by the total ridership. Other common approximations are to use a high-value ticket discount price, or the price of a monthly pass divided by a common number of trips.
# Fare Pass Model
In some models, there is a separate step to forecast which individuals decide to buy transit passes. Individuals with passes would then have a zero marginal cost to riding transit.
Ultimately, it is up to the modeler to decide what an appropriate level of approximation is for the purposes of the transit system that is being modeled and the effect that it will have on the project that the model is being used for.