Couple of shots my g/f got from the back seat while we rided in Tehran, Islamic Republic of IRAN - 4 to 5 persons on the 50-125cc bikes is soooo common there:
Also they carried unimaginable stuff on the scooters:

Had those wierd windscreens, some scooters even had a roof for the rain! etc.
Stunning stuff

Most of all - they take very little room in the traffic compared to cars and trucks.