I've helped out for Bike to Work Week in spring and fall when I lived in Vancouver. Vancouver expanded 2 (if not also 3!) Bike Weeks throughout the year.
Later this May, when we visit our families in Toronto, we'll be taking in the lst day of Bike to Work Week, in Toronto. There's several big group commuting rides from several directions of Metro Toronto to converge into 1 downtown location. Hope it doesn't rain to deter many cyclists. Lookin' forward to it...I participated in my first Bike to Work Day (now it's wk.) over 15 years ago when I lived in Toronto.
Except for Vancouver, the Bike to Work Week stuff tends to locate their energy pit stops/information tables in the downtown core locations or mid-town. It's a serious challenge to bring in the numbers in the surburban areas.
Perhaps other folks here in the big cities have different experiences.