The standard 40ft RTS bus will hold 41 seated, and about 27-31 standees.
The Nova LFS low floor bus will hold 35 seated, and about 50 standees.
The Gillig low floor bus will hold 34 seated, and about 50 standees.
All numbers are just estimates... each ride is different. Strollers and different sized people will change the number. Also, many times, folks refuse to go all the way down the back aisle on the Nova LFS, or onto the rear deck of the Gillig.
And then of course, there's always the last few who are determined to squeeze on somehow.