The law in Ontario is a little iffy on this… or not.
(2) No person riding on a bicycle designed for carrying one person only shall carry any other person thereon. R.S.O. 1990, c. H.8, s. 178 (2).
So then, you can only have two people on a bicycle that is intended for two passengers. Does that only mean tandems or bicycles with child seats? One of my bikes has a large rear rack that can comfortably seat an adult, but does it have to be plastic with a seat belt to be considered a seat? If the passenger is an adult must my bicycle accommodate them with pedals and a saddle?
Either way, turns out Cathryn and I need to practice “the hop” on our shared rides on my bicycle. We’re pretty good at starting from a standstill, but this will seriously up our game.