Some fare products only allow travel at particular times – such constraints can be expressed using USAGE PARAMETERs. Others only allow travel for a particular duration; FARE STRUCTURE ELEMENTs with TIME STUCTURE FACTORs can be used to describe the different durations. Furthermore, sometimes journey time is related to journey length, so for example a longer time is allowed for a two zone trip than a one zone trip; all this can be precisely specified in NeTEx.
Temporal conditions may also apply to the purchase or refund of tickets, likewise expressed as USAGE PARAMETERs attached to fare products.
As well as the routine examples given above, NeTEx can also handle more complex cases. For example, in the periphery of a large city, off peak times may start at different times in each station since by the time a journey to the centre starting from the station ends, the peak period will have ended.