The prospect that the nation’s biggest retailer is interested in building a 50,000-square-foot store in the Shirlington area of Arlington has prompted the county board to consider whether it should require big-box retail stores to get special scrutiny.

Wal-Mart is reportedly looking into building one of its urban-style consumer emporiums along I-395 at Four Mile Run, now an industrial site, but close enough to a residential area to prompt the support of two neighborhood associations including one that represents Nauck, one of the county’s oldest historically African American areas.

County officials are concerned about the potential impact of traffic and related adverse effects on the area, said Chris Zimmerman, chairman of the Arlington County board.

“It’s not a ban on anything,” Zimmerman said. “It’s really a planning measure aimed at developments of a particular scale. The aim is how we accommodate development to our neighbors. We spend a lot of time making sure [developments] fit into their surroundings.”

The proposed amendment to the county’s zoning ordinance would require “large format sales establishments” of more than 50,000 square feet, or with more than 200 parking spaces, get a special permit from the board. Auto dealerships are excluded, as are most grocery stores and the existing Costco store in Pentagon City, among others.

Although the change in the ordinance was prompted by a report from a developer that Wal-Mart was interested in the Shirlington land — where a property owner would have a right to build without special restriction — the proposed change would also apply to other industrial areas along Lee Highway and in the Shirlington Crescent/Four Mile Run area.

Big-box retail stores bring in nearly five times as many daily trips as a hotel or office, and almost 10 times as many daily trips as a high-rise residential area, according to a national engineering standard.

The amendment was introduced without fanfare or advance notice in July, just before the county board adjourned for the summer. The blog ArlNow first reported the action July 14. Since then, it has gone to the county’s planning commission and to a hearing before the full county board. The local economic development commission expressed concern that the proposal “has been rushed through without adequate consideration of potential unintended consequences,” but Zimmerman noted that the measure has been public for three months.

The Northern Virginia chapter of the Commercial Real Estate Development Association said the proposal “infringes on the rights of owners to develop their property and diminishes the value and usefulness of property.”

Wal-Mart did not respond to requests for comment on the development or the proposed zoning change.