The Transportationist: Elements of Access: Diurnal Curve (http://transportationist.org/2015/04/06/elements-of-access-diurnal-curve/)
(https://transportationist.files.wordpress.com/2015/04/pasted-graphic-18.png)
QuotePeople possess Circadian rhythms, they operate on a 24-hour cycle, and about half that time is daylight. Going to the place where that (work) activity occurs follows a pattern: Leave home early enough to arrive at the destination at a desired time. Do something there. Leave there (after, say, 8 hours) and return home. There are many complexities.
QuoteThe graph has two peaks: morning and eventing. These peaks are the "rush hours" of common complaint, when more people want to use the transportation system than capacity is immediately available, leading to congestion. This graph shows both the supply provided by the public transport system (more seats are made available during the peak) and the demand of users. The supply clearly responds to the demands. The afternoon or evening peak is usually higher (and almost always broader) than the morning peak, as we organize more activities after work than before.