The Washington school board has forbidden three of its members to travel out of town at public expense after learning that the three had already spent for more on trips this year then the other eight board members combined.

"There were certain people who were taking advantage of it," said Carol Schwartz, the board's vice president who led the move for the travel ban, which went into effect four weeks ago. Mrs. Schwartz said that about $10,000 of the $13,000 that the board had available for travel this year had been spent by April 1, which was six months before the end of the current budget year

"There's been no set policy (on who can spend the travel funds)," Mrs. Schwartz said, "but unless something was done, if a conference came up in the next few months and somebody wanted to go, they might find out that the money was all gone."

The three board members who have been barred from taking any more trips at least until July are Barbara Lett Simmons, Bettie G. Benjamin, and John Warren. Since July 1, 1976, the school system's finance office reported, Mrs. Simmons has spent $2,807 on seven trips; Mrs. Benjamin, $1,975 for four trips, and Warren, $1,478 for four trips.

During the same time, the other eight board members have spent a combined total of $2,783 on travel, while $390 from the travel fund has been used by board attorney David Splitt.

"It's just a matter of jealousy," said Ms. Simmons, who heads an educational consulting firm, BLS and Associates, Inc., as well as serving on the D.C., School board.

There are people on the board who very much resent the fact that I am known nationally, and they are not," Mrs. Simmons said. "But I didn't known because I am on the school board, and they wouldn't be invited to some of these meetings, like I as, if they sat on the school board for 200 years.

"Some of these people who go to meetings just sit there like a sponge and use up the oxygen," she added. "Every place I've been to I've made a speech."

Warren, who works for the National Public Management Institute, a non-profit group that helps local government officials, said the board members who have taken more trips are the ones who "have a broader vision of things."

"If other people don't want to participate," he added, "that's up to them."

Under a resolution passed by the board last month, the remaining money in this year's travel account is to be alloted equally among the eight low-spending board members up to a maximum of $300 apiece.

Mrs. Schwartz said the board plans to adopt a detailed policy on travel by October. She said the money probably should be divided equally but that extra amounts should be provided for board members who hold posts in national organizations.

"Since we are dealing with public money, there should be a more equal opportunity for all the public officials to go to conferences or take training that is useful to them," said board member Betty Ann Kane.

"Certainly, an equal allocation will not require anyone to go anywhere, but letting the travel money be spent simply on demand, as it has been up to now, puts us in a position that looks suspicious to the public. We should be above suspicion."

Mrs. Simmons agreed that the school board should adopt guidelines about its travel, but she said they should deal with the purpose of trips and what board members are doing on them, rather than with trying to make sure that all board members spend equal amounts of money for travel.

"Do you let a blithering idiot go some place?" she asked. "Or do you send someone who brings accolades to your school system?Do you let someone go who just occupied space and takes in oxygen, or do you send someone who contributes?"

But Mrs. Kane rejoined, "Who is to decide who makes better use of the money?"

Until the travel ban went into effect, Mrs. Simmons' trips this year included the Las Vegas Convention of the National Association of School Administrators, meetings in Miami and Philadelphia of the National Alliance of Black School Educators, a conference in New Orleans of Title One (low income) parents, and education workshops in Williamsburg and Blacksburg, Va. She also attended the national school boards association convention in Houston, along with nine other D.C. board members.

Several board members suggested privately that Mrs. Simmons used some of the trips to promote her consulting firm, a charge Mrs. Simmons strongly rejects.

"People may call me up later and inquire about my firm," she said, "and I'll tell them. That may be a spin-off of it. I'm not denying that, but that's not the purpose of my trips. They have nothing to do with my business."

On the other hand, Mrs. Simmons charged that Mrs. Kane used her board-paid trips as "family vacations" because she brought her husband along to the school board association conventions this year in Houston and last year in San Francisco.

"I took my husband along because he's useful," Mrs. Kane said. "He paid all his own expenses. He went to meetings and took notes, and we discussed them. It certainly wasn't a vacation. It's work."

Mrs. Benjamin, who went to workshops and conferences in San Diego, New Orleans, and Chicago, as well as the Houston convention, said, "It's good to get out of your own little environment and see how other school districts deal with problems. I think each board member should have an opportunity to go if they want to, but if they don't go or can't, then others should go."

School board president Therman Evans, who supported the travel ban, could not be reached for comment yesterday. A school board secretary said Dr. Evans was out of town, but not at board expense.