Classic Rock evolved from several earlier radio programming formulas that were attempts to provide alternatives to tightly formatted Top 40 radio stations of the 1950s and 1960s. One of the first was freeform radio, in which disk jockeys were given total control over the music played. Although music genres varied, freeform stations tended to feature music selections generally not heard on Top 40 stations. Freeform radio was also referred to as underground, progressive, or alternative radio.

     The Progressive radio format emerged from freeform radio, but it had some structure designed by a music programmer. The Progressive format incorporated a rotation system for music categories. Disk jockeys followed the category rotation system but still had considerable latitude in the selection of specific songs. Progressive served as a bridge between freeform radio and the more mainstream AOR format that developed in the 1970s.

     Like its predecessors, AOR was a rebellion against Top 40 in that it avoided chart hits in favor of longer album cuts by popular artists. It brought with it music sweeps-uninterrupted series of songs-and a less-structured, more laid-back announcer delivery style. Initially, AOR appealed to a young­ adult, primarily male audience. During the 1970s AOR grew in popularity as Top 40 waned.

     During the 1980s, however, AOR began to lose younger listeners as Top 40 regained popularity with the emergence of MTV. Younger listeners could no longer relate as well to standard AOR artists such as the Doors, the Grateful Dead, and the Moody Blues. As a result, a splinter of AOR, called classic rock, emerged to appeal to adult listeners. The format features hits of the past but with a harder musical edge than other popular music formats for adults. Typical artists in the Classic Rock format include Bob Seger, ZZ Top, Bruce Springsteen, and the Rolling Stones.

     The Classic Rock format first appeared in 1983 in Dallas on WFAA-FM. The format often is classified as part of the vintage rock category that also includes the Oldies format. Classic Rock is different from Oldies in that it features rock hits with a harder edge and generally does not include music from the 1950s and early 1960s. Arbitron, a radio audience research firm, includes Classic Rock as one of the 15 formats it recognizes nationally and defines Classic Rock's content as "the same universe of music as Album Rock, but without much current rock."

     Some radio programming analysts have predicted that the Classic Rock format will disappear within a decade. They see adult listeners shifting to modern rock or alternative formats in the future, but as the 1990s drew to a close Classic Rock was gaining in popularity among "baby boomer" listeners. According to Arbitron, the format's share of the national radio audience has continued to increase over the past few years, with a peak of 4.9 percent in 2002.