The Fairfax County Board of Supervisors yesterday ordered its staff to study how a proposed Major League Baseball stadium just over the Loudoun County line would affect traffic on Fairfax's already congested roads and its nearby neighborhoods.

The order came on the eve of what is expected to be a new round of talks between Major League Baseball and the groups seeking to bring a team to the District or to Northern Virginia.

Sources familiar with the matter who spoke on condition of anonymity said they expect meetings today and tomorrow between bargainers for baseball and the two separate and competing groups representing the city and Northern Virginia.

The meetings, to be held in the Washington area, were to involve fine-tuning of the local groups' proposals but were not believed likely to lead to any sudden breakthrough in the protracted bargaining.

The possibility of an imminent decision on whether Major League Baseball will come to Northern Virginia appeared to spur the supervisors to explore how the proposed 42,500-seat stadium and surrounding development would affect their community.

Supervisor Catherine M. Hudgins (D-Hunter Mill) said she was concerned that Fairfax has, so far, been left out of discussions.

"While this is a facility that is being proposed for Loudoun County, this will have a major, major impact, and the discussion has been without us for a long period of time," she said.

The study request came after Loudoun County Board of Supervisors Chairman Scott K. York (I), in an unusual visit to the Fairfax board, said he understood that the stadium would have an effect outside Loudoun. If Loudoun is chosen as the site for a stadium, York said he would encourage Fairfax officials and residents to join in the public discussion.

"I want [people] to understand that although they are citizens of Fairfax County, they are citizens of the community."

Baseball officials, who are nearing the final stages of a search for a home for the Montreal Expos, have been considering four sites: Northern Virginia, the District, Norfolk and Las Vegas, according to senior league sources.

York said yesterday that he was told by officials of the Virginia Baseball Stadium Authority -- which would be responsible for financing and building the stadium -- that a final decision on the future of baseball in Northern Virginia could come this week. Gabe Paul Jr., the authority's executive director, said he told York that it is his "hope" that a decision is made by the end of the month but said Major League Baseball hasn't given him any timeline.

County Board Chairman Gerald E. Connolly (D) said there is no question transportation issues would arise if the stadium were constructed. Supervisor Michael R. Frey (R-Sully) cautioned colleagues and residents to keep in mind that if baseball goes elsewhere, the Loudoun land is slated for "dense" development.

Fairfax supervisors voted last year to oppose putting a ballpark near Fort Belvoir's former Engineer Proving Ground in Springfield. Supervisors have cited transportation and other concerns in pulling themselves out of the running to host the Expos.

Also yesterday, the Fairfax supervisors divvied up about $48.7 million in "carryover" funds from last year's $2.73 billion budget. The cash is available largely because of higher-than-expected revenue from property and other taxes.

About $7.8 million was set aside for the county's rainy-day fund in case of an economic downturn. And $8.1 million was set aside as a reserve fund, most likely to be used next year to help ease the tax burden on homeowners.

Higher-ticket expenditures approved by the board included $5.4 million for new Emergency Medical Services positions and $2.8 million to expand and renovate the county's courthouse complex.

The board funded several new one-time projects, including setting aside $50,000 to transform a portion of the former Lee District satellite tax office into a permanent site for the Franconia Museum. The volunteer-run group, which holds history tours and collects photos and maps, runs exhibits at the Franconia Governmental Center and local libraries. The board also voted to spend $400,000 for an analysis of traffic in the Tysons Corner area.

Supervisors also earmarked $10,000 for Metropolitan Washington Ear Inc., a nonprofit Silver Spring-based group that allows sight-impaired residents to call and hear recorded newspaper and magazine articles read by volunteers.

Staff writers Michael Laris, Martin Weil, Lori Montgomery and Thomas Heath contributed to this report.

Loudoun official Scott York says he is open to hearing from people in Fairfax if a Loudoun site is chosen.