(15 Jun 2014, 9:59 am)G-CPTN wrote That must be a maximum weight limitation - the longer vehicle (with more seats) will be heavier, and, conversely the shorter vehicle will be lighter allowing more standees.
Hmmm:- maybe it's a licensing limit? as the following shows all lengths max out at 70/71 pax:-
http://www.wright-bus.com/streetlite/options.html
Do buses have 'evacuation' requirements (like aircraft)?
Seems pretty odd that they all take the same number of people, although I doubt 70/71 people on any sized Streetlite would be quite a squash!