Hello, I am posting this message on the recommendation of Mr. Elie Guitton, who suggested I reach out to Mr. Alain L'Hostis. I am currently conducting research on accessibility times for local amenities, based on the "15-minute city" framework. I have found limited information regarding two specific points: The rationale behind the 15-minute threshold: What is the specific basis for this 15-minute limit? Is it an arbitrary/political threshold, or is there a formal academic justificat