Dire Problem / Drastic Cures : Transportation: The old answers--more roads and mass transit--may have reached a dead end. Brainstormers have come up with some surprising twists and turns to untangle our urban gridlock.

The fanciest new ideas for making our lives better may surprise you.

They include no place to park, lots of apartment houses and a ban on neighborhood parks that lure families onto the streets.

These and other planners’ dreams were on view earlier this month at UC Irvine. Transportation experts from around the country met under the auspices of the National Academy of Sciences to swap cures for an ill that is hardly new to the San Fernando Valley--the fact that Americans are driving more all the time, and neither road-building nor mass transportation seems able to keep up.

“Every year since 1960, the federal government has consistently forecast a 2.5% increase in driving, and the actual increase has consistently been 3.5%,” Alan E. Pisarski, a transportation consultant and author of “Commuting in America,” said at a meeting of more than 50 planners.

The conferees’ conclusion can be fairly summed up as, “The sky is falling.”

What’s happening on the streets is like heart trouble. Arteries are clogged, and disaster is imminent. Easy mobility, the lifeblood of suburbia, may soon disappear unless the link between the single-family house and the private automobile is broken.

It’s particularly bad for those living in more distant bedroom communities such as those in the Antelope Valley, “exurbs” in the planners’ argot. As the streets fill to capacity and beyond, the theory goes, houses in these distant zones might become so unattractive that prices would drop. That point was made by Daniel Brand, a Boston-based consultant, when he told his colleagues that congestion is close to the point where it “threatens the value of our recent massive increase in private investment in suburban and exurban housing and land.”

Ultimately, one participant said, the would-be suburbanites of the future may be “forced by economics or local zoning policies to forget the big back yard and maybe even the single-family house itself.”

The grids are locking fastest in California and other high-growth states, but almost no area is immune. The population of greater St. Louis declined nearly 4% in the 1980s, but driving increased 20%.

The reasons are numerous. The cure, according to these experts, lies not in building freeways or subways--there simply is not enough money to keep up with the demand--but in changing the way cities are arranged.

With remarkable agreement, the planners argued that housing of the future should be high-density, a far cry from the one lot-one family American Dream.

Planners repeatedly cited a landmark study by the California Department of Transportation, which concluded that a doubling of residential density results in a one-third drop in driving.

For present and future suburbs, the brainstorming sessions produced a regimen that, like a healthy fibrous diet, will strike some as repellent and others as thrilling.

“We don’t have any good news for those who hope to continue driving at will,” said Frederick W. Ducca, a Federal Highway Administration planner. “The statistics tell us that those days can’t go on much longer.”