The Arlington County Board voted unanimously yesterday to oppose any reductions in the four-people-per-car rule for rush-hour traffic on I-66. The action came after a hearing at which citizens overwhelmingly argued against easing the rule.

At the suggestion of Board Chairman Ellen M. Bozman, the board agreed that no reductions in the four-person restrictions should be considered for at least a year after the planned Dulles Airport Access Road connector is opened. The board's position is to be presented at a Thursday public hearing on the issue sponsored by Rep. Frank R. Wolf (R-Va.).

The connector road, which would link the Dulles Access Road and I-66 inside the Beltway when it opens next fall, is expected to have a major impact on I-66 traffic volumes because I-66 will pick up more commuters from the toll road and because people going to and from the airport will not have to adhere to the passenger limitations.

"A bargain was made between the governments and the people," said Catherine Hughes, a resident who testified before the board. "To change it would be shameless--dangerous."

The rush-hour restrictions, as well as a ban on trucks, were part of the fedral government's concessions to Arlington residents who bitterly fought the road for decades, arguing that I-66 would primarily benefit outlying areas at Arlington's expense. Those objections were voiced again yesterday as all but one person testified against reducing the passenger restriction.

In other action yesterday, the board split 3 to 2 along party lines to approve a 20-cent increase in the water-sewer tax rate to $2.31 per 1,000 gallons, a rise that will add $16 to the bill of the average house.

The board also approved nearly $2.3 million in community development block grants, the largest chunk of which will go for weatherizing homes. The board argued for two hours over a $5,000 appropriation to the Tenants of Arlington County, an umbrella organization for tenant associations. The board's two Republican-backed independents charged that the money was a "political gift" to the group, which has many Democrats in its membership. The Board's Democrats countered that the group's activities are needed by tenants.