ION - Waterloo Region's Light Rail Transit

[tomh009]

I think our buses have 5-digit numbers, but there are lots of them. Is there any pattern or logic to the numbering of the buses? Like are the first three digits a contract number and the last two are the buses within that contract or something like that?

GRT bus numbers reflect the year and a sequential number.

Pre-2000 Kitchener Transit numbers were a two-digit year and a two-digit sequence (e.g. 9201 was the first bus of 1992).

If I recall correctly (it's been a long time ...) in the 1970s and early 1980s the buses were numbered consecutively, with no year coding.  These were the "old-look" GM buses in green and pale yellow (I think), and the first of the "new-look" buses in silver and orange (were those the colours?).
But I can't find any references or photos online.