ABC has decided that "Cop Rock" is ready to roll on out of here.

The network has canceled the bizarre hybrid - half "Hill Street Blues," half "Hello, Dolly!" - because of abysmal ratings. The final installment will air Dec. 26.The big question is how this disaster ever got on the air in the first place. And there's a two-word answer - Steven Bochco.

One of television's most successful producers - "Hill Street Blues," "L.A. Law," "Doogie Howser, M.D." - Bochco is the proverbial 500-pound gorilla in Hollywood these days. Especially at ABC, where he has an exclusive multiyear contract to deliver new series.

Of course, the network itself is largely to blame for "Cop Rock." Like all networks these days, ABC is desperate for successful shows. And, like all networks, ABC is ceding an increasing amount of control to producers who have a good track record.

And there may lie the root of the problem - Bochco has so much power there's no one willing to tell him when a pet project isn't a thoroughbred, it's a mangy mutt.

Bochco said not too long ago that if ABC dared to touch a single frame of "Cop Rock," it would be the last frame of film the network would ever receive from him.

Not that either Bochco or ABC can be faulted for having the courage to try something new and different. But, while appearing before the media last summer, Bochco appeared to want applause simply for the attempt.

What he failed to realize is that being different isn't enough. A show has to be good, too.

And "Cop Rock" wasn't. It might have been a strong, adult police drama without the music. But the quality of the songs - and the inability to mesh the music with the drama - left "Cop Rock" as an often ludicrous mess that turned viewers off in droves.

ABC will replace the cops with lawyers - "Equal Justice" is set to return to the schedule on Jan. 9.

"Equal Justice" just barely missed making the the fall schedule (it was beaten out because of Bochco's clout) and did fairly well in the Wednesday, 9 p.m. slot in a tryout last spring.

KUTV NEWS: Dan Webster, Ch. 2's news director since March 1989, has resigned to accept a position with the Associated Press.

Webster's departure comes as no surprise. It's been rumored for weeks that he was looking for another job. His final day with KUTV will be Nov. 21.

The longtime television newsman isn't leaving TV behind. Webster is returning to Washington, D.C., to accept the newly created position of AP's director of marketing for television services, where he'll market AP's television services to stations around the county.

Webster's career includes stints as a news director in Albuquerque, in various positions with NBC News and with "USA Today: The Television Show."

At KUTV, he was responsible for the creation of the 5 p.m. newscast and was involved in negotiations to return anchorman Terry Wood to the station. He also brought a different look to Ch. 2's newscasts - sort of a sleek, updated approach reminiscent of "USA Today."

But his stay was by no means an unqualified success. The public never really took to Ch. 2's new look - ratings declined on both the 6 p.m. and 10 p.m. newscasts and the 5 p.m. show has struggled greatly to find an audience.

And recent layoffs in the newsroom - layoffs that were to some degree beyond Webster's control - have caused an even larger drop in morale at Ch. 2.

KUTV plans a "national search" for a new news director. In the meantime, Diane Orr, KUTV's vice president of special programming and news, will assume direct responsibility for the news. Day-to-day operations will be supervised by Amy Levin, Bryan Shiffer and Larry Warren.

RATINGS: The special "Cheers" episode toasting the sitcom's 200th episode not only finished as last week's highest-rated show, but was the most-watched program of the season to date - beating out even the World Series.

Not only that, but "Cheers" has been No. 1 six of the eight weeks since the season began.

The show pulled a phenomenal 29.5 rating and 44 share. That's the highest numbers by a comedy series since an episode of "The Cosby Show" that aired almost two years ago.

NBC also won the Sunday night movie battle. Part 1 of "The Big One: The Great Los Angeles Earthquake" finished 15th, while ABC's "Call Me Anna" tied for 18th and the broadcast premiere of "Fatal Attraction" on CBS was 27th.

For the week, NBC was first with a 13.7 rating and a 22 share, according to the A.C. Nielsen Co. (Each rating point equals 931,000 homes and the share is a percentage of household watching television.) ABC was second with a 12.8/21 and CBS third with a 12.0/20.

However, the Big Three networks are still separated by less than a ratings point after eight weeks of the 1990-91 season - NBC is No. 1 with a 13.3/22, CBS is No. 2 with a 12.9/

22 and ABC No. 3 with a 12.6/21.

And CBS can't be too terribly unhappy. For the first time in years, the network has added a pair of shows to the Top 10 - "Murphy Brown" and "Designing Women" have become regular residents at the top of the ratings. (They tied for No. 4 last week.)

America was largely indifferent to "Who killed Laura Palmer" - the pivotal episode of "Twin Peaks" tied for 52nd, but did improve on its normal numbers.

And the new "Wiseguy" didn't get many people excited, either. Stephen Bauer replaced Ken Wahl in the role Saturday, but the two-hour movie finished a weak 79th (and finished behind "Twin Peaks" during its second hour).

As usual, ABC won the ratings battle among the network newscasts. "World News Tonight with Peter Jennings" was No. 1 (for the 44th week in a row) with an 11.6 rating and a 21 share. "CBS Evening News with Dan Rather" was second with a 10.1/18, and "NBC Nightly News with Tom Brokaw" third with a 9.1/18.

THE TOP 10: 1. "Cheers," NBC; 2. "60 Minutes," CBS; 3. "A Different World," NBC; 4. (tie) "Designing Women" and "Murphy Brown," both CBS; 6. "Empty Nest," NBC; 7. (tie) "America's Funniest Home Videos," and "Roseanne," both ABC; 9. "Murder, She Wrote," CBS; 10. "Unsolved Mysteries," NBC.

NEWS WHEN?: Still no official word on when KSTU-Ch. 13 expects to have a news operation of its own up and running, but don't expect it to be January, as Fox Chairman Barry Diller announced this past summer.

Ch. 13 still hasn't hired a news director, let alone the rest of the staff. And with just 56 days remaining until 1991 arrives, a January startup would seem to be a bit of a challenge. Sometime next spring - or next fall - looks more likely.