Having already committed a huge public relations blunder by calling for stringent regulation of street vendors, the Greater Washington Board of Trade is about to give another lesson in how not to win friends.

Previous calls for legislation that would have limited vendors' sales and restricted their access to sidewalks produced a controversy, pitting street hawkers against the area's largest business group.

Vendors called the attempt to restrict their activities restraint of trade. The Board of Trade, on the other hand, cast vendors in the role of public nuisance. There is no assurance that vendors will pay sales taxes, they obstruct pedestrian traffic and sell merchandise that should only be sold in stores, the board contended.

A task force set up to study the street vending issue has been disbanded in the wake of the controversy, and city officials have decided to reorganize the body. The reorganized task force of 33 will include eight members from the business community, two of them from the Board of Trade.

The same stumbling block that prevented the previous task force from accomplishing its aim will confront its successor. And the outcome will probably be the same unless common sense intrudes.

Recent statements by Board of Trade officials indicate that their organization's position on street vending remains essentially unchanged.

The board's policy states that:

* All businesses, including vendors, should collect and pay taxes and pay appropriate fees for government services.

* Vending should return to its original purpose of providing an opportunity for District residents to offer unique goods and services.

* Vendors should be permitted to sell only cut flowers, hand-crafted goods and food for immediate consumption.

Although the board's original proposal will be presented to the new task force for "background," its continued defense of that proposal suggests that the debate will turn on the same arguments.

"Our position will change in light of what the new task force does," declared Peggy Wall, manager of the board's community development bureau.

Nonetheless, Wall insists that vending should be a "positive contribution to street life." It has gone beyond the original concept that was intended, she adds.

In other words, Wall conceded, "No, the basics of our position haven't changed."

Vendors should pay a fee to do business in a public place, and they should collect and pay sales taxes, Wall insisted.

That's a tenable position, and vendors would be unwise to oppose it. In fact, the city doesn't need a task force to resolve that issue. People who elect to do business in the District are required to pay fees and taxes, and vendors should expect no less.

The mere fact that they choose to sell their wares on the city's streets shouldn't qualify them for exemption from taxes and fees. That's the way the free enterprise system works.

But the Board of Trade would deny vendors that opportunity altogether by insisting that the street merchants sell only what the board approves--handcrafted goods, food for immediate consumption and cut flowers.

"We think delineating merchandise adds to the positive ambience of the street," Wall allowed.

Its concern for the ambience of the street notwithstanding, the Board of Trade is, in effect, advocating actions that would stifle competition. With vendors restricted to selling food, flowers and souvenirs, established merchants would maintain control over the marketplace without the worry of competition.

The inventory on a typical vendor's stand doesn't include designer dresses, fur coats or major appliances. So, what harm is there in vendors selling plants, T-shirts, cheap leather goods and jewelry?

"We think thats's not what vending should be in this city," Wall countered. "Vending has to be a positive contribution to street life."

The mayor's new task force on vending ought to consider the positive contribution the practice makes to persons who might, otherwise, be unemployed in a city where the unemployment rate is still higher than 10 percent.

To be sure, some street vending activities are run by major business concerns that franchise their operations.

Yet, the fact is that the people who choose to become vendors and are willing to endure the sun, rain or frigid weather should be allowed to make an honest living.

Stronger enforcement of tax laws resulting in vendors' contributing to the tax system could produce substantially more revenues for the city. And with the rules of the marketplace applied equally to the sidewalk and the store, competition should have a positive effect on the ambience of the street.