Most of the many traditions of the Maryland General Assembly are revered and adhered to by all. But one legislative tradition that goes back through five governors creates antipathy, frustration and as much sniping back and forth as anything short of the abortion issue.

It is called the truck-cover bill.

The history of the bill can be traced to the early 1960s and has been nearly as much a part of the legislature's annual sessions as all-night sine die parties on the 90th day.

The issue is simple: Should open-bed trucks be required to have covers or tarpaulins to prevent debris from spraying onto other vehicles? Proponents of the measure maintain that uncovered loads can create hazardous road conditions, cause accidents and damage other trucks and cars.

The trucking industry and its supporters have argued, with considerable success, that implementing such a law would be expensive for truck owners and dangerous for truck drivers, who would have to be responsible for putting the covers on, taking them off, or keeping them in place.

Every year for the last 20 years, opponents have convinced at least one committee, either in the House or Senate, that they are right and the bill's proponents are wrong.

"I should like to point out that if you kill this bill you will join very distinguished company," trucking lobbyist John Hanson Briscoe, a former Speaker of the House, told the House Environmental Matters Committee last week. "This bill has been through five governors and four committee chairmen in the House. I would suggest that you ask yourself why this bill has never been passed."

Supporters contend that the bill has never passed because of parliamentary tricks and all of the money that the trucking lobby has spent wining and dining legislators.

"I think the first person who introduced this bill was Cicero, in the Roman Senate," quipped Sen. Howard A. Denis (R-Montgomery), who keeps a rock on his desk that he says flew off an uncovered truck. He shows it each year when he testifies in favor of the measure. "The bill is like 'The Perils of Pauline,' only each year they find a different way to kill Pauline."

The bill has become more than just a hardy perennial that blooms briefly each year only to wilt under lobbying pressure. Del. Joan B. Pitkin (D-Prince George's), one of this year's sponsors, said that the idea has "taken on a life of its own."

Opponents accuse supporters of having a vendetta against the truckers. Proponents accuse the truckers of not caring about the public safety.

The principal sponsors of this year's bills are Sens. Arthur Dorman (D-Prince George's) and Denis, and Dels. Ida G. Ruben (D-Montgomery) and Pitkin.

Dorman has been promoting truck covers for 16 years, since his days in the House. The first bill that Denis introduced when he came to the Senate in 1977 was a truck-cover bill. Ruben and Pitkin watched helplessly last year when former Environmental Matters chairman Torrey C. Brown, an avowed opponent, refused even to bring the bill up for a vote in the committee.

"That bill has been killed for 20 years and it will be killed for another 20 years," Brown said then. "It will never get out of my committee."

The committee, however, no longer is Brown's. The Johns Hopkins physician was defeated for reelection. The new committee chairman is Larry Young (D-Baltimore), who has said that he will be guided by the will of the committee, rather than imposing his will. His vice chairman, William R. McCaffery (D-Prince George's), favors the bill.

With a new committee chairman in the House and because the Senate has approved such a bill in the past, the measure's supporters were excited over the bill's chances when the current session began. No more.

"We've got an uphill fight," Dorman said the other day. "The way they've changed the [Senate] Constitutional Public Law committee this year, it's going to be difficult. But we're not that far away. If we turned a few votes around, we could do it, or at least get a compromise."

Dorman now has three, and possibly four, votes on the eight-member committee, but he is having a hard time finding the necessary fifth vote. In the House, Pitkin and Ruben think they have nine solid votes, or four short of the needed 13.

One compromise would be passage of a "no-peaking" bill. Currently, Maryland law does not limit the peak height of bulk material in an open truck as long as the material is no closer than six inches from the top at the sides.

Regardless of what measure passes or fails to pass, the public hearings on the issue each year produce some of the most colorful exchanges between legislators and witnesses during the legislative session.

Last week, after 40 witnesses had paraded through Environmental Matters during an afternoon-long hearing, nothing had changed.

Pitkin and Ruben opened the hearing by pointing out that similar bills had been passed in Florida and California and that Tennessee appeared likely to pass a law soon.

"There is a trend in this direction," Ruben declared.

"Trend? What's the trend? Tennessee?" retorted Del. James E. McLellan (D-Frederick), who has voted against the idea four times and says that he intends to do so a fifth time this year. "If I didn't know the sponsors better, I would think you were out to get the trucking industry with this kind of bill."

Truckers and their supporters insist that forcing truckers to cover loads would be more dangerous than leaving them uncovered.

"There have been no fatalities because of uncovered loads," said Robert Clay, chairman of the Maryland Minority Contractors Association. "If you force truckers to cover their loads, there will be . . . . Climbing on top of a large truck to cover or recover a load, especially in bad weather, will be very dangerous."

"Did you bring your truck here today?" asked Del. Paula C. Hollinger (D-Baltimore County), a long-time proponent of the bill.

"No, I didn't," answered Clay.

"Tell you what," challenged Hollinger, the most dimunitive member of the legislature, "you or one of the other opponents bring your truck in one day and we'll see if I can climb it. If I can, that means any of your people can do it."

Briscoe suggested that state police could spot-check trucks to see if they conform to the current laws against overloading. But Del. W. Timothy Finan (D-Allegany), a freshman who is considered neutral on the bill, pointed out that spot checks might be ruled unconstitutional.

The usually unflappable Briscoe, who had proposed that the committee write a letter to the state police suggesting it was "shocked" that spot checks weren't being made, could only reply: "Well, I'm not a constitutional lawyer."

The committees may vote on the bills within the next two weeks.

"If we ever get this made law," Denis said. "I want on my tombstone: 'He got the truck-cover bill passed.' "