Howard County Executive Elizabeth Bobo borrowed an idea from neighboring counties yesterday in proposing to forbid new development in areas where roads are very congested and schools very crowded.

The proposal, called an adequate public facilities ordinance, is Bobo's first attempt to carry out growth-control measures called for in her recently approved 20-year blueprint for growth in the county.

Those controls are needed because Howard County -- sandwiched between Baltimore and Washington -- is now seeing the kind of growth problems that have long plagued much of the region.

Last fall, 62 percent of the county's schools were crowded and about 15 percent of the area's roads had more traffic than they were designed for, county officials said.

Bobo, a Democrat, warned that those conditions will worsen if her proposed legislation is not adopted by the County Council.

"This should put the county in an excellent position to thrive as an economic center while preserving the high quality of life for which it is noted," she said.

Bobo has given community and business groups until Aug. 17 to comment on her plan, after which she plans to introduce it formally.

The legislation is patterned loosely on laws in seven Maryland counties, including Montgomery, Prince George's and Anne Arundel.

Some of those jurisdictions have gone further than the Howard proposal, blocking proposed development if fire, police and sewer services are inadequate. But Bobo said she hopes other services can be maintained through other means, including existing law.

Under the Bobo plan, developers could not build unless they first determine that roads within two miles of their project or two major intersections near their project -- whichever is closest -- can handle the traffic it would generate. Residential developers would carry the added burden of ensuring that their subdivision would not make nearby schools crowded.

If the roads are determined to be too crowded, developers could make road improvements or pay the county to make them. They would be permitted to team up with other developers in upgrading the roads.

If area schools are too crowded, developers would need to find land for a future school to handle their proposed development. They might also be required to build their subdivision in phases rather than all at once.

Bobo said she opted not to allow acceptance of money from a residential developer in lieu of school sites because land suitable for schools is now in short supply in the county.

However, R. Robert Linowes, a prominent development lawyer in Maryland and the District, said that adequate facilities laws do not guarantee that growth is controlled. "Sometimes they work, and sometimes they don't," Linowes said.

The laws are least effective when they are applied selectively or when counties fail to follow through on making developer-financed improvements, he added.

"In too many instances, these laws only apply to certain people or certain conditions, while exceptions are made for others. Once that happens, the law loses its effectiveness," Linowes said.

Bobo said her staff took pains to develop a law that would keep subjective judgments to a minimum. To do that, the proposal relies on special manuals that spell out what constitutes a crowded school or congested road. She said she would fight attempts to grant any developer a waiver.

Under Bobo's plan, once developers offer improvements, land or money to mitigate problems, they would enter into an agreement with the county that is binding on both parties.

Community and business leaders in Howard County scrambled to get a copy of the long-awaited document yesterday. Bobo had promised to deliver the legislation ever since she persuaded the County Council to delay adoption of similar legislation offered by council member Angela Beltram (D-District 2) last year to halt development in areas with crowded schools.

"I'm on my way to a briefing right now," said Alan Rifkin, an attorney for the Howard County Forum, a coalition of business, housing, farming and minority groups.

He said the forum will apply two tests to the proposal: "One, does it provide for housing that is affordable at all levels. And, two, does it maintain an active economic development base for the county."

HIGHLIGHTS OF BOBO'S PROPOSAL

Developers would be denied permission to build a structure that would generate excess traffic congestion within two miles of the site or at two major intersections, whichever is closer. Construction of houses would be restricted by the enrollment capacity of nearby schools.

Developers stymied by congested roads could win approval for a project by improving existing roads or subsidizing new roads.

A developer stymied by crowded schools could win approval by donating land for a new school. However, if existing schools exceed capacity by 10 percent, a developer would have to donate land and agree to build the residential project in phases.

Government land would be exempt. Housing for the elderly and people with disabilities would not have to meet requirements for adequate schools.