Would you wait an hour to be reduced to a quivering plup? How about dropping 10 stories at a speed that will pin your eyelashes back?

The line forms to the right for America's new wave of the traditional scare machines: roller coasters. And millions of people are lining up, hoping to get frightened out of their wits.

Roller coasters have shot to a new and sudden popularity, and the competition is raging among amusement parks to see which one can come up with the most hair-raising twists, turns, and hills.

More roller coasters have been completed or are being built this year than during any other year in recent history, according to Gary Kyriazi, author of "The Great American Amusement Parks" and generally considered the expert on roller coasters. "The only time when there were more being built was during the 1920s, and then there was a new one opening up every week," he says. Kyrizai estimates that there are more than 100 roller coasters now operating in the United States - some 30 of them built since 1972.

One of the latest additions to the roller coaster craze is the Colossus, about 25 miles north of Los Angeles at Magic Mountain amusement park. Park officials claim Colossus to be the world's largest roller coaster, covering about 10 acres of land and built with more than 1 million board feet of wood. According to Magic Mountain's Jack Ryan, its 105- and 115-foot drops are the two longest in the world. That's a 10-story drop, and the train hits about 65 mph by the time it bottoms out on the first one.

Colossus also signals a return to wooden coasters despite the fact that most of the newer ones are made of steel, which offers a smoother, quiter ride. "Parks are beginning to look for wood coasters mostly for nostalgia," comments Lace Dillon of International Amusement Devices, one of two wood coaster manufacturers in the United States.

The real sizzlers in the world of roller coasters are the ones that take riders upside down, and manufacturers pore over the drawing boards thinking of new ways to do it.

The Arrow Development Company, for one, has several of its Corkscrews in parks all over the country. The train follows a route laid out like a corkscrew on its side, going through as many loops as the park management wants to invest in.

Knott's Berry Farm, 25 miles south of Los Angeles, has put together a delightful little ride called Montezooma's Revenge. It does not mess around with turns or hills but gets right down to business. At the start, a catapult similar to those used to launch planes from aircraft carriers shoots the train directly into a loop, accelerating from zero to 55 mph in five seconds. Once out of the loop, the train slides up a hill. You are looking straight up into the clouds, and dreading that the train will fly off the track - which you cannot see. But, no, that would be too kind.

The train slides backwards down the hill and goes through the loop again - yes, you guessed it - backwards. Then it's backwards up another impossibly steep hill and back down into the station. Total elapsed time: 30 seconds. The ride would curl the toes on Evel Knievel, but Knott's shovels 1,500 people an hour through it.

The cost of a coaster is enough to set executive knees wobbling - without the ride. They start at about $2.5 million and have so far hit a high of $6 million with Colossus, but they are the principal draws in amusement parks and pay their way with a double-back, triple reverse loop to spare.

One of the most recent additions to the steel loopers is the Loch Ness Monster at Busch Gardens in Williamsburg, Va. It stretches nearly a mile over a hilly ravine and includes two loops, a 114.5-foot drop at 55 , and a darkened tunnel ride through a mountain.

In a class by itself, as always, looms Space Mountain at Disneyland here, and at Disney World in Florida. The ride starts at the top of the inside of the mountain and zips through an incredible arrangement of special effects and unnerving turns. The rider becomes completely disoriented because the whole thing takes place in the dark. The special effects come from 80 projectors and 150 speakers and include whirling galaxies, "Star Wars"-like lasers and enormous asteroids.

Officials at all the parks are anxious to point out their elaborate safety systems, which include complex and automatic breaks that are triggered on the track should anything go wrong, and, in the case of Space Mountain, an impressive computer system that plots each car as it zips through the dark.

Why do people voluntarily submit to such a stomach-churning experience?

Kyriazi says there are no thrills left in American life, so people seek them out in amusement parks. Disney's Hench theorizes that the desire goes back to a fundamental instinct for survival. "It satisfies a basic human need to meet a challenge and survive it."

Otherwise, roller coasters are just plain fun.

With that in mind, this reporter felt that, in the interest of first-hand accuracy, roller coasters should be ridden before written about. So, dragging a friend kicking and screaming to the gates of Colossus, I surrendered to a minute and a half of insanity. It lived up to its reputation as fast, furious and frightening, and reduced my poor friend to blank stares and an occasional giggle.

I, on the other hand, remained cool and unperturbed and was able to walk away with a firm step - just as soon as five attendants pried my fingers out of the safety bar. Of course, I could not blink for six hours, but as soon as my eyelids relaxed and rolled back down everything was fine.