9 min
Car-Free September: The Commute Challenge Your Team Didn't Know It Wanted
Car-Free September is an opt-in niche challenge anchored to World Car-Free Day (September 22) and the year's best commuting weather: participants log car-free days — bike, walk, transit, carpool, and park-and-ride hybrids all count — because the commute is a twice-daily slot that already exists, making it the purest form of habit stacking, with a documented mood dividend over sitting in traffic.