It’s ridiculous really that people who have paid for tickets on public transport don’t get to sit down (especially on long journeys).
Today’s invention offers an alternative in the form of flexible plastic seats like those which sometimes appear in playparks by way of replacements for traditional heavy wooden ones.
There are almost always handholds on the shoulders of seats bordering the aisle in a bus or train. Using these, to each seat on one side of the aisle would be attached permanently a flexible, rubberised seat/strap unit, so that it hangs down beside the seat when not in use.
Once the seats fill up, rather than have to stand, people can grab the free end of the seat and attach it to the handhold on the seat on the opposite side of the aisle. This would be achieved using a robust, easy to use clip…which would support a passenger’s weight but disconnect easily when flicked upward (e.g. when evacuation is suddenly needed).
This arrangement would be no less safe, in the event of say a fire, than having to fight one’s way past numbers of standing passengers. Sitting down might well result in fewer injuries when some kind of collision occurs.