RICHMOND -- Several legislators admitted the other day something that regular observers of the frantically paced Virginia General Assembly have long suspected: They don't always know what they are doing.

Senate Minority Leader William A. Truban (R-Shenandoah) said he is "not qualified" to vote on some of the bills that are "one-half-inch thick" that he reads at 10 p.m. in his hotel room.

"We have been blowing smoke," agreed Senate Majority Leader Hunter B. Andrews (D-Hampton). The public is "entitled to legislative efficiency and deliberation" but instead, he said, it is offered "a railroad train" that goes so fast that "people don't have an opportunity to express their views."

Such rare bipartisan confessions came Thursday during debate about a proposed constitutional amendment that would permit lawmakers in future years to take one or more midsession breaks of up to 10 days.

The amendment's sponsor, Del. Clinton Miller (R-Shenandoah), said that a need for closer examination of the budget was the driving force behind his idea. But he said the recesses also could provide more time for public hearings on issues such as abortion, elected school boards and transferable development rights.

Under the present timetable, even the most controversial subjects seldom get more than a one-hour hearing because legislators must race off to another committee, or break for the daily floor sessions.

"It's exasperating for people to drive to Richmond from all over the state for a hearing, and then be told they only have one minute to present their view," Miller said.

After the frantic sprint toward Saturday's adjournment, the 140 members of the Virginia General Assembly, who represent the state's 6.1 million residents, will have dispensed with about 2,000 bills and resolutions.

They dealt with them sometimes with wisdom, occasionally by mistake and almost always in haste.

To get their work done, the lawmakers hold hearings as early as 7:30 a.m., eat lunch during floor debates and often are still at work late into the night and on weekends.

That is not to say the legislators don't take time out for nightly receptions given by lobbyists, but even their sharpest critics concede that they are hard workers.

By comparison, Maryland, with 188 legislators for about 4.8 million residents, follows a comparatively relaxed schedule that usually runs from Monday night to Friday afternoon.

The difference is that Virginia's legislature meets for 60 days in even-numbered years and 30 in odd-numbered ones (extended to 45 or 46 days in recent years), while Maryland's assembly meets for 90 days every year.

So while Maryland is just halfway through its 1991 session, Virginia is in its final frenzied week.

One of the most hectic dates on the assembly's calendar is crossover day, the deadline for each house to act on its bills. C. Flippo Hicks, who has been patrolling the halls of the Capitol as a lobbyist since 1953, calls it "passover," because it's so easy for legislation to win approval on that day without close examination.

In rushing to meet the crossover deadline, which this year was Feb. 4, the House passed six similar bills on historic preservation, and three of them came through the Committee on Counties, Cities and Towns, a staff member informed Chairman Mary A. Marshall (D-Arlington) recently.

"Would it be fair to say this committee is firmly committed to the diversity of conformity?" Marshall quipped.

To the chagrin of Fairfax County's three lobbyists, officially called liaisons, two measures that won easy approval in the House on crossover day could have hurt the state's most populous jurisdiction.

It wasn't until someone in the county's assessment office back home read the fine print that it was discovered that the bills, which give tax breaks to restaurants, could cost the county millions.

"It sent them to the moon," said Sue Mitterader, head of the county's Richmond operation, who quickly went to work on killing the bills in the Senate. With the help of Sen. Joseph V. Gartlan Jr. (D-Mount Vernon), the offending measures have been sidetracked in the Senate Finance Committee, though they could be revived.

"I've just come through my worst week in 20 years," said Hicks, who works for the Virginia Association of Counties.

Hicks missed a provision in a House-passed bill that attempts to fill a gap in the enforcement provisions of the Indoor Clean Air Act that went into effect last July by requiring county attorneys to handle violations.

The problem with that, Hicks said, is that many smaller counties have no such office, and would have to hire a lawyer every time there was a complaint.

Hicks caught up with the measure before the Senate Education Committee. He persuaded the Senate panel to make enforcement the responsibility of the commonwealth's attorney, which every county has.

"I never thought I'd say it," said Hicks, who was around when biennial sessions were replaced with yearly meetings in 1973, "but it's time for a change again."