The District of Columbia probably will simply redeck the crumbling Whitehurst Freeway rather than tear it down and replace it with a lower highway, Mayor Marion Barry said yesterday.

Prelimary studies show that repaving the road and reconfiguring its exits would be the most cost-effective approach for dealing with the 33-year-old elevated freeway, the mayor said at a budget hearing of the Senate Appropriations subcommittee on the District.

The freeway runs between the Potomac and Georgetown from Rock Creek Parkway to Key Bridge.

Other options that the city has studied include tearing the freeway down and building either a lower elevated highway or a ground-level road that would run along K Street NW and connect to Key Bridge. City officials had not indicated previously which option they preferred.

Repaving would cost about $70 million, while the other options could cost between $90 million and $95 million, Barry said. A final decision will be made in the fall, he added.

In another development at yesterday's hearing, the mayor for the first time acknowledged that the city's controversial effort to transfer the $12 million cost of street lighting and traffic signals to District ratepayers will be in litigation for some time, regardless of what decision the Public Service Commission makes on the proposal.

If the PSC approves the city's plan, Pepco plans to take the matter to court, Barry said, and if the PSC rejects the plan, the city will litigate.

The city's original fiscal 1984 budget had assumed D.C. would save that $12 million in street-lighting costs, but the District appropriations subcommittees in both the House and Senate have been skeptical that the transfer could be accomplished by Oct. 1 when the fiscal year begins, if at all. The city submitted its proposal to the PSC last Thursday.

The House appropriations subcommittee last week added language to the District's budget requiring the city to pay its electric bill until the issue is resolved.

Yesterday Barry said he is committed to paying the bill and asked Senate Subcommittee Chairman Arlen Specter (R-Pa.) to endorse the House language.

"That would take care of Pepco's concerns of being paid," Specter replied. "And if you can win your case in court, more power to you--no pun intended."

At the broad-ranging hearing, the mayor also made these points:

* He supports efforts by Specter to require education and training for prisoners at Lorton Reformatory and to add federal funding to the D.C. budget for such a plan, intended to be a national model.

* The city is putting together a profile of prisoners at the overcrowded D.C. jail to see which ones might be candidates for diversion to alternative forms of sentencing, such as community service.

* He would like to move toward a system of requiring that court cases be brought to trial within a certain time after a person's arrest, but he is not sure what time limit would be appropriate for the District.

Specter said he would like to find supplemental federal funds to the D.C. budget for required training and education programs at Lorton. "It is long past due to make a national effort so people won't be released as functional illiterates with no training or skills," he said.