1. Issuance

The PTAR was issued in 1970 and was implemented at the beginning of the 1971–72 television season (the week of September 13–19, 1971). It was re-examined periodically and underwent several modifications since its initial implementation.

The PTAR was instated over the concern that the three major television networks (ABC, CBS, and NBC) dominated the television program production market, controlled much of the programming presented to the public, and inhibited the development of competing program sources. The FCC believed that PTAR would ultimately increase the level of competition in program production, reduce the networks' control over programming decisions made by their affiliates, and thereby increase the diversity of programs available to the public.

To ensure that independent companies would have access, the Financial Interest and Syndication Rules (commonly known as "fin-syn") was instituted at the same time by the FCC. It prohibited networks from owning syndication arms. Existing syndication divisions operated by the networks were forced to be spun off as new companies independent of network management (such as Viacom, which was originally created by CBS to distribute its content, and it eventually expanded outside of program syndication and distribution in the succeeding years post-spinoff).

2. Recent

Immediately prior to its repeal, the Prime Time Access Rule applied only to owned-and-operated or affiliated network stations in the 50 largest television markets. It restricted these stations from broadcasting more than three hours of network programming during the four-hour prime-time block each evening and established the first 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 and network programming of a special nature.

To comply with the PTAR, most local television stations presented at least one syndicated game show between 7:00 and 8:00 pm; ironically, these were usually additional episodes of existing network daytime game shows (occasionally with a different host), distributed by companies that before 1971 had been subsidiaries owned by the networks (such as the former CBS property Viacom and former ABC property Worldvision Enterprises) and produced by the same production companies at the same studios as their daytime counterparts, effectively circumventing the purpose of the rule. Other programming that was often scheduled in these time slots were revivals of Hee Haw and The Lawrence Welk Show (both shows that had been canceled by their respective networks, CBS and ABC, in the spring of 1971, before PTAR took effect). Still others (most notably WIS in Columbia, SC) used the hour to carry their local evening newscast, a tradition that continues to this day.

The loss of the extra hour forced networks to eliminate a significant amount of its programming schedule; this led to an exacerbation of an already-existing trend in television programming known as the "rural purge", where programming that targeted less affluent, rural or older viewers (most notably, several series carried by CBS including The Beverly Hillbillies, Mayberry R.F.D. and Green Acres) was cancelled by the networks.

3. Elimination

The PTAR was eliminated on August 30, 1996, the commission having determined it was "no longer necessary" as a tool to promote independent production or affiliate autonomy.^[1] While the major networks have not reclaimed the traditional "access" period in early primetime, this is most likely due to pressure from affiliates to retain control of one of the more profitable parts of their programming schedules. Several syndicated programs (such as Entertainment Tonight, Wheel of Fortune and Jeopardy!) are still broadcast in the "prime access hour", and have earned audiences equal to or greater than many network shows. Other broadcast stations have expanded local news operations to carry local newscasts in the said hour. In 2010, Fox was allowed to present World Series games that started around 7:30 pm. Eastern Time, presumably under the hope that games would not run into the 11:00 p.m. (Eastern) hour (though in practice, this still consistently occurs despite the early start). In 2014 and 2015, CBS moved its Thursday prime time to start at 7:30 p.m. for the first eight weeks of the season to allow for a full pregame show for Thursday Night Football, a move which was emulated for NBC and Fox's carriage of the same package.

Smaller networks such as Pax TV launched with full 24-hour schedules after the rule change. Some networks, though, had programmed the "access" hour despite the rule, particularly Spanish-language networks that hold responsibility for the majority of their affiliates' programming schedules, such as Univision and Telemundo.

4. Sunday Nights

A 1975 revision to the PTAR allowed networks to program the 7:00 p.m./6:00 p.m. time slot on Sundays, and the majority of the major networks have done so ever since. A consequence of this time slot is that the show has to be either a news or information program (such as 60 Minutes) or a show that is both accessible to all ages (especially children) and have some educational content.

ABC has programmed America's Funniest Home Videos in the slot for much of the time since 1993 (except for a period from 1997 to 2002, when ABC broadcast The Wonderful World of Disney in the 7:00 p.m. hour), while CBS has shown 60 Minutes in the slot consistently since 1975 except on very rare occasions. NBC has mostly broadcast Dateline NBC in the slot since 1996, though since regaining NFL broadcasting rights in 2006, during football season the network airs Football Night in America in the slot as a pre-game show to its NBC Sunday Night Football broadcasts. Most of the Winter and Spring, however, NBC (as well as ABC and FOX) has aired programming in this time slot that is not a news or information program (such as the aforementioned Dateline NBC). Such programs are either re-edited versions of shows that normally would air in the 8–11 PM Prime Time slot, or theatrical films intended for family viewing (such as animated films).

Even today, some networks still air aural and/or visual bumpers (i.e. "We'll return after these messages") in the 7/6 PM Central time slot for younger viewers to understand the difference between a program and a commercial—these bumpers, one of the original requirements of the time slot, is exempt from news and information programs such as the aforementioned 60 Minutes.

The slot has been used by the networks to broadcast run-over programming from NFL games, since the NFL broadcasting contracts require the games to air in their entirety (this happened as a result of the Heidi Game in 1968, in which NBC cut away from an Oakland Raiders-New York Jets game to air the television film Heidi, prior to the Raiders' comeback late in the fourth quarter). While CBS "shifts" its Sunday evening schedule to start after its NFL coverage concludes, Fox has utilized a different approach: the network completely pre-empted its lineup until the last game it held the right to broadcast in each region had finished until 2004, upon which it joined its prime-time lineup in progress (pre-empting portions or even the entirety of programs scheduled to air in the "first" hour of its prime time schedule following the game's designated time slot). Similarly, if necessary, major tournaments in professional golf are also treated in this manner; since 1987 (the year Daylight Saving Time was moved earlier), The Masters Tournament has begun to finish into the hour. The U. S. Open and Men's PGA Championship, depending on the region, also can be overrun into the time slot, with Pacific Time Zone tournaments allowing networks to run into prime time hours.

Since 2005, Fox has aired the post-game show, The OT, in the slot as "filler" programming between its NFL coverage and The Simpsons at 8:00 pm, with its length depending on how late the final game ends, since NFL games with a 4:25 p.m. (Eastern) start time almost always end by 8:00 pm, even if the game goes into overtime. Fox has continued the practice for Monster Energy NASCAR Cup Series races, as the Daytona 500 and on occasion, a West Coast Swing event such as the Auto Club Speedway round, was designed to creep into the 7:00 p.m. hour, and the U. S. Open, typically held on the Sunday closest to the longest day of the year, will also do such. Before that, the 7:00 p.m. hour on Fox was seen similar to that of the Friday night death slot on all of the networks, as several shows near the end of their runs (such as Malcolm in the Middle, Family Guy and Futurama) were scheduled to air in the time period but ultimately got pre-empted by Fox's NFL coverage. This tradition has continued during the off-season, with the most recent examples of shows burned off on Sundays at 7:00 p.m. half-hour being 'Til Death and Sons of Tucson during the spring and summer of 2010, and Mulaney in 2014.

On October 7, 2018, The CW resumed programming a prime time lineup on Sunday nights. However, unlike its previous effort to program that night from the network's launch in September 2006 (a byproduct of originally adopting co-predecessor The WB's 30-hour weekly base schedule upon The CW's launch) until it ceded the timeslot to its affiliates in September 2009, The CW opted to only to offer programming during the "common prime" slot (8:00 to 10:00 pm. ET/PT) offered on weekdays and Saturdays by the conventional broadcast networks that have launched on U.S. television since Fox's expansion to include prime time program offerings in April 1987. This move marked the first such instance of a major U.S. television network not programming that hour since the 1975 PTAR revision was implemented.^[2][3][4][5]

The content is sourced from: https://handwiki.org/wiki/Engineering:Prime_Time_Access_Rule_(US)