A rush hour or peak hour is a part of the day during which traffic congestion on roads and crowding on public transport is at its highest.he name is sometimes a misnomer, as the peak period often lasts more than one hour and the rush refers to volume of traffic, not rate of its flow. Rush hour is from 6–10am (06:00–10:00) and 4–8 pm (16:00–20:00). Peak traffic periods may vary from city to city, from region to region, and seasonally.