More than 200 Northern Virginia commuters debated the car-pooling restrictions on I-66 at a public hearing last night, and most had the same message: they're tired of life in the slow lane.

But Virginia Highway Commissioner Harold King told reporters that he will not even consider easing the road's HOV-4 rule (which reserves the highway for so-called high-occupancy vehicles containing at least four persons during rush hours) until the end of the year.

It will take at least that long, he said, for the state highway department to complete construction of a road connecting I-66 with the Dulles Access Road and to measure the connector's effect on I-66 traffic.

"It looks like maybe by this coming December we could have sufficient data" to make a decision, King said. "I want to see the data before we make any changes."

King's statement seems sure to hinder efforts by a vocal group of area politicians, led by Rep. Frank Wolf (R-Va.) to allow three-person car pools to use the 10-mile stretch of I-66 inside the beltway during peak traffic periods.

The HOV-4 restrictions were imposed in 1977 as a compromise after Arlington residents balked at plans for an eight-lane highway through their community and the project was cut to four lanes.

Federal regulations specify that the restrictions may be modified by the Virginia highway department, with the agreement of federal and area transportation officials.

The U.S. secretary of transportation may also change the restrictions upon consultation with state and area officials.

Wolf, as well as Virginia's Republican Sens. John Warner and Paul S. Trible Jr., made it clear that they favor easing the restrictions.

"This highway is vastly underutilized," Wolf said, arguing that it is operating at between 18 and 28 percent of its capacity during rush hours. "There is no other area in the United States that has a four-person car-pool requirement."

The area's three members of Congress, sitting on a panel with state and federal highway officials, heard from more than 50 speakers, most of whom had driven through rush-hour traffic to attend the hearing at George Mason Junior-Senior High School in Falls Church.

Among their number were car-pool members and Arlington residents, who favored keeping the restrictions intact. But most spoke for commuters from developing Fairfax and Loudoun counties, complaining about recent highway department figures showing that the road carries only about 10 cars a minute during its peak periods.

"The most expensive 10 miles of highway ever built was opened last year, and the very people who need it the most are disenfranchised," said WMAL traffic reporter "Capt. Dan" Rosenson. "At that rate, the multimillion-dollar bike path along the side could carry more vehicles than I-66 does."

Other complaints were lodged by the handicapped, as well as motorcyclists and drivers of small foreign cars, who are barred from the highway automatically because their vehicles can't hold four people.

Proponents of the restrictions argued that the occupancy requirements will ultimately allow I-66 to carry far more people at peak times than it would otherwise be able to do, and said that existing usage figures are inadequate because they count only cars--not people.

They argued that car-pooling restrictions also encourage the use of mass transportation and energy conservation.

"One of the lessons we have clearly learned from the Shirley Highway express lanes is that the opportunity to bypass congested roadway conditions is a powerful incentive to increase vehicle occupancies," said Arlington County Board Chairman Ellen Bozman. "That incentive would quickly disappear if the express lanes were to become congested as well."

Without car-pool restrictions, proponents said, I-66 traffic would quickly overload the Theodore Roosevelt Bridge and turn the $250 million highway into a vast parking lot.

State highway officials have argued that it is not fair to judge the effectiveness of the restrictions yet because the highway has been open for only three months. They said it will take more time for commuters to organize themselves into car pools.

"I came here to hear from the public and all I've heard are politicians," said Del. Vincent F. Callahan (R-Fairfax), as he watched a parade of elected officials march up to the speaker's podium. "I guess it's an election year."