Late-night news in a few markets, CBC Television, in Canada that are located in the Eastern and Pacific Time Zones. In contrast, stations in the Central, Mountain, Alaska and Hawaii–Aleutian Time Zones air their final local newscasts of the day at 10:00 p.m. local time, with stations in other time zones following their own schedules. Late local newscasts are typically scheduled in-between a network's prime time and late night programming, allowing for a sizeable lead-in audience for the newscasts. Stations that are affiliated with Fox, The CW, MyNetworkTV, or that are independent stations tend to air their late newscasts at 10:00 p.m.
Prime Time Access Rule hour of prime time (7:00–8:00 p.m. Eastern Time and Pacific Time, 6:00–7:00 p.m. Central, Mountain, Alaska and Hawaii–Aleutian Time) as the "prime access hour". By the early 1980s, the PTAR had introduced a policy amendment prohibiting stations in the 50 television markets with the highest prime time viewership from broadcasting more than three hours of network programming during the four-hour "prime time" block. Stations had to find original programming to fill during the "prime time" fraction. However, the rule exempted certain types of programming, such as overruns of live sports events, special news, documentary and children's programming, and certain sports