A Montgomery County Circuit Court judge struck down Montgomery's new truck cover ordinance yesterday, saying the County Council exceeded its authority in enacting the bill that would have required truck drivers to cover their loads when using local roads, beginning next Tuesday.

Judge Paul H. Weinstein, ruling on lawsuits filed by a Baltimore trucking company and two self-employed drivers, said that under Maryland law, the power to enact such legislation rests with the General Assembly, not local jurisdictions.

"I'm obviously disappointed that the decision precludes the county from doing what the state will not do," said County Executive Sidney Kramer, who signed the truck cover bill on Nov. 24.

The County Council, frustrated by the legislature's repeated failure to pass such a law, had unanimously approved the measure. Supporters cited substantial property loss, injuries and even deaths that they said have been caused by gravel, stones and other debris spilling from uncovered truck loads onto highways.

The measure was strongly opposed at the county and state level by trucking industry representatives, who describe it as costly overregulation of their business.

The truck cover debate has raged for years in the Maryland legislature, which killed a truck cover bill last Friday, for the 26th year in a row. The Virginia Senate, for the first time, passed a truck cover bill for nonfarm vehicles last week, and the House must now consider it, although it earlier defeated a similar bill. The D.C. Council gave tentative approval to a similar measure Tuesday night.

Kramer said he and council members would consult with County Attorney Clyde (Rocky) Sorrell before deciding whether to appeal the judge's decision.

"We're glad," said David Cahoon, a former County Council member and a lawyer, who argued the plaintiffs' case before Weinstein last month. "It was clear from the beginning. The authority of local jurisdictions to regulate motor vehicles is preempted by the state."

Uncovered truck loads are "a problem, and all the citizens are aware it's a problem," said Merle Steiner, an assistant to council member William E. Hanna Jr., who sponsored the bill. "We've got to find a way to protect citizens and their property. We're just going to have to approach it another way and try to do it next year."

Sorrell and other officials said they expected a legal challenge to the local bill from the day it was passed. "There was a good argument to be made by the other side" that the Maryland Vehicle Law prohibits counties from enacting truck cover ordinances, Sorrell said. "We recognize that argument. But we also thought we had a good argument. It wasn't something that was crystal clear."

The Maryland Vehicle Law, which includes numerous road-use provisions, bars counties from creating their own provisions, with some exceptions. The law states that a "local authority, in the reasonable exercise of its police powers, may restrict the use of highways" under certain circumstances.

Sorrell said he interpreted the Maryland Vehicle Law as allowing counties to enact truck cover ordinances. But Weinstein agreed with Cahoon, who argued that the statute bars such ordinances.

Montgomery's truck cover law was the second and stronger such local law in the state. In Harford County, Assistant County Attorney Alan Cason said yesterday that Harford's ordinance, passed in the early 1980s, requires truck drivers to cover only those loads that appear likely to spill into traffic. Cason said the ordinance has not been challenged in court.