If everyone had a free pass for all public transport then you can make the free pass only free at certain times, with a standard ticket price for other times.

If everyone had a free pass for all public transport then you can make the free pass only free at certain times, with a standard ticket price for other times. Old retired folk don't need to get anywhere for 9 a.m. or be in a mad dash to get home at 5.30 p.m. They get a free pass that only works between 10 and 4. Essential public sector workers, e.g. school teachers get a free pass for the commuting hours or whatever is needed for their shift patterns. They could also have free evening and weekend travel not given to the senior citizens. School kids get a different pass again. The incentives can be many, if it is always kept as a perk that is seen as such even if 99% of the population can get it, then you can do the rationing. Until recently UK police had free passes to use transport networks when off duty. The cost cutting government got rid of this perk. This hacks people off, people in the police are no longer thinking the government is looking out for them. They no longer are made to feel part of a bigger family of public sector useful people because they don't get the guest treatment on the rails. Whether they used the pass or not is irrelevant, it is the treatment that matters. There were no incidents of off duty police officers travelling for free en masse and causing paying passengers to no be able to get a seat. So rationing is one of those problems that falls into the category of 'nice to have'.