PROPONENTS OF limitless growth in Loudoun County keep inventing new ways to railroad their designs into law. The latest blitz comes from the county Planning Commission, which after months of speculation has abruptly unveiled the details of the largest single growth proposal in the county. With no serious time for residents to digest details -- the actual language was made public only in the past three weeks -- the county has scheduled a public hearing at 5:30 p.m. today in the Government Center in Leesburg, hardly a convenient time for commuters or residents observing Rosh Hashanah.

The Comprehensive Plan Amendments -- "CPAMs" in the planning lingo -- could result in rezoning some 9,200 acres that would give a green light for nearly 28,000 residential units, about seven times the current number in these areas and probably seven times as many daily car trips. Transportation planners estimate that nearly every road in the county will be affected.

The development proposal in question, near Dulles International Airport in the eastern part of Loudoun, has been in play for months, but its precise dimensions, and the likely impact on local roads and traffic, were unknown. Though county officials say the public has been informed regularly, complete information is only now showing up; all along, residents have had minimal opportunity to present their views. In the past 12 months, the Planning Commission has held a grand total of two sessions at which residents could speak -- one in March and another in April, long before the final product was shaped. At both sessions people had a maximum of three minutes each to speak, without benefit of any meetings on specific parts of this large package of proposals.

When a majority of voters elected their current leaders, they chose supporters of torrid growth -- and it's underway with a vengeance. Still, the cozy relationships of county leaders and developers too often have given concerned citizens the bum's rush. One session is not a fair opportunity for residents to gauge the impact of the amendments or to present their views. Another session should be set, with adequate time for the public to prepare for it.