A lot of things happened in the last quarter century, but the covering of loads wasn't one of them. It has been 25 years since the first bill was introduced in the Maryland General Assembly to ban trucks from driving with uncovered gravel or other loose loads, and many similar bills have been rejected ever since. A mere mention of "covered loads" today elicits snickers and groans, even from legislators with short memories.

Yesterday they were at it again. Representatives of trucking firms that oppose this year's bill turned up at the Senate Judicial Proceedings Committee with complaints about the cost and danger of covering loads. Supporters of the measure, as usual, retorted with complaints about flying rocks on highways and smashed windshields.

Sen. Howard A. Denis (R-Montgomery), one of the bill's sponsors, was back again too, wielding the same rock he pulled from an uncovered truck to produce at a hearing held years ago. Mary Anne Reynolds of the American Automobile Association, another bill supporter, said about 30,000 insurance claims are filed in Maryland each year for broken windshields caused by flying objects.

Don Prescott was back again, too. He runs a business with 126 trucks in Southern Maryland and said he paid about 80 claims last year -- about half of those that were filed against him -- to motorists whose cars were damaged by debris flying from his trucks and cement mixers.

He said that the debris is "a nuisance," but that the alternative is worse: Canvas covers could fly off trucks and strike cars -- blinding the drivers and causing accidents -- and employes could be injured climbing on trucks to cover the loads.

After the hearing, Denis said he didn't know how the bill would fare. Sometimes it has passed the committee only to be defeated elsewhere. "It's like the Perils of Pauline," he said, "except in this little drama Pauline gets run over by the train in the end."