Are passenger capacity numbers tested when vehicles are built etc. Noticed on GNE solo sr 626 yesterday that the standees were 21. Wouldn't want to be either sitting or standing with that amount on. I know other vehicles have large standee numbers also but how is it decided the amount permitted?

It's usually limited by weight rather than the physical limitations these days but our Sapphire Streetlites have a maximum capacity of 67 which I have managed once.

If its limited by weight why do the signs state 33 seated 21 standing. 1 wheelchair passenger. 28 seated 40 standing. What's the difference between 4 people seated or 12 people standing when the capacities vary so much. That cannot be weight surely?