MIAMI — Our roller coaster slowed as it approached the precipice, then stopped, the front hanging over the edge. From my seat at the end of the front row, I could not see the track below, just empty space. We teetered there for excruciating moments, while I contemplated my folly and certain death.

Then the car slid smoothly over the brink and we were diving down, down, down, and I was screaming in real terror, before the coaster entered a loop and started back up again.

I was on SheiKra at Busch Gardens Tampa Bay, the only coaster in Florida with a 90-degree plunge and the scariest of the 20 coasters I rode that week.

My mission: To size up Central Florida's coasters, pick the best and survive the rest.

In Central Florida, 11 coasters have opened since 1999 — 13 if you count Disney's two virtual coasters. From Manta's Superman-like flying position to SheiKra's 90-degree dive, to Dragon Challenge's cars that are suspended from the wheel platform rather than built on top of it, they represent some of the innovations of the newest generation of coasters.

They were part of a coaster building boom that peaked at the turn of the millennium. In Central Florida — and around the world — the rides are faster and taller than their predecessors, with more loops, inversions and unique elements than ever before.

That boom ran its course. Now, only Busch Gardens has a ride under construction that is rumored to be a coaster. Scuttlebutt on fan websites is that it will be a fast-launch coaster named Cheetaka. The Tampa park isn't commenting, except to say the attraction "will combine the two things that Busch Gardens does best: up-close animal encounters and thrill rides."

None of Florida's parks has a record number of coasters — Cedar Point in Sandusky, Ohio, has 17 — but it's an impressive concentration just the same: six at Busch Gardens, three at SeaWorld, two each at Universal Studios and Universal's Islands of Adventure, and seven at the Disney parks, including two simulators.

Coaster fans credit Central Florida with some top-tier coasters, among them Manta at SeaWorld, SheiKra and Montu at Busch Gardens, Incredible Hulk and Dragon Challenge at Universal's Islands of Adventure, Revenge of the Mummy at Universal Studios, and for sentimental reasons, Space Mountain at Disney's Magic Kingdom, Florida's oldest theme park coaster.

But for the most ardent coaster fans, who travel the country — and even the world — in search of high-speed thrills, Orlando is not considered a coaster hotspot.

"The roller coasters in Orlando are not record-breaking rides and some of the coasters are conservative — primarily Disney's collection," said Eric Gieszl, founder of UltimateRollerCoaster.com. "While Orlando doesn't have a huge collection, they do have some outstanding roller coasters.

"Tampa on the other hand has built some notable coasters over the years and they tend to be much more aggressive. Busch Gardens is well respected amongst coaster fanatics and has some of the best roller coasters found anywhere."

BUSCH GARDENS

This is where I kicked off my own tour of theme-park coasters. My parameters: no kiddie coasters, no water rides unless they include mechanical coaster propulsion elements such as the chain lift hill on Journey to Atlantis, no rides that simply drop but don't go anywhere.

Starting with Gwazi, a wooden coaster that rattled my bones and repeatedly lifted me off my seat, I rode five of the park's six coasters before lunch: Montu, an inverted coaster that turned us upside down seven times; Scorpion, a older coaster that still carries a sting; Cheetah Chase, which makes you feel you're about to fall off the edge of one of its hairpin turns; and Kumba, loud, fast and dizzying, with three seconds of weightlessness.

I was exhilarated and feeling fearless, but my stomach was unsettled. I blamed Cheetah Chase.

After lunch and some animal encounters that threatened neither my limbs nor my equilibrium, I was ready to face SheiKra. I don't have much trouble with motion sickness — really, who wouldn't feel a little queasy after riding five coasters in rapid succession? — and am not bothered by heights or speed, but I don't like edges. SheiKra has a 195-foot drop, about half of it straight down.

At the bottom of that plunge, after I realized I had survived Central Florida's most daunting thrill ride, I knew everything would be downhill from there.

DISNEY

Thrill rides are not a significant part of Disney's repertoire of family-oriented attractions designed around sometimes-elaborate stories. With four parks in Orlando, Disney has only five actual coasters, plus two simulators.

I started at Magic Kingdom with the oldest, Space Mountain, whose overhaul last year — new games in the queue, darker ambience, updated decor — gave it a more contemporary feel than its age (35) would indicate; it still has plenty of thrills. On Big Thunder Mountain, the "collapsing" mine scenery is more threatening than the ride itself. Then to Animal Kingdom, for Expedition Everest, with its startling downhill run in reverse, and Primeval Whirl, with its spinning cars. The best of the actual coasters was my last: Rock n Roll Roller Coaster, with a high-speed launch and three inversions, accompanied by Aerosmith.

At Epcot and Downtown Disney, I designed my own coasters, then got in simulators to experience them. Once I tried them, I wished I'd drawn in more thrills. I could have redesigned them, but I wanted to spend the time riding real coasters.

UNIVERSAL

Like Disney, Universal designs its rides around stories, but is more adventurous in its thrill rides at its two Orlando parks.

At Islands of Adventure, I rode coasters that were already among my favorites: Incredible Hulk, with a high-speed launch and inventive loops, and Dragon Challenge, whose dueling inverted trains had me whooping with glee, my feet flying free.

Next door, at Universal Studios, both of the coasters lost points with me — neither turns upside down once: Revenge of the Mummy, the only indoor coaster at the two parks, and Hollywood Rip Ride Rockit, where riders choose their own soundtrack for the experience. "Something by the Rolling Stones would fit here," I thought. That's when I learned that coasters are not designed for people over 50. There was none of our music on the list. I settled for M.C. Hammer"s "U Can't Touch This," and we were off.

SEAWORLD

SeaWorld Orlando came late to the thrill-ride party; it didn't open its first — Journey to Atlantis, half flume ride, half roller coaster — until 1998. I rode it and got the usual soaking, and then tackled Kraken — fast and floorless, with seven inversions.

It was here, on this newcomer's grounds, that I encountered the best ride of my tour, Manta, opened just over a year ago, which simulates a manta ray gliding smoothly through the water.

We sat upright, held in place by a lap bar, harness, and flaps in front of our ankles. Then the mechanism rotated our heads down, feet back. Thus suspended, we soared out over nothingness, flying on our bellies like Superman.

We climbed the inside of a loop and dove down the other side, head first, the scenery a blur of color as we rushed by at this unaccustomed angle. Then we glided up a second loop, this one with the rails twisted around it so the manta spiraled gracefully around the structure, as smooth as a stripe on a peppermint stick.

BREAKING RECORDS

The last coaster building boom saw a string of records made and broken. Coasters reached record heights — 200 feet, then 250 and 300; now there are two coasters taller than 400 feet. At least five coasters reach speeds of more than 100 mph. The traditional enclosed sit-down car has been replaced by stand-up coasters, suspended cars, floorless cars. There are more ways of being turned upside, of feeling weightless, more coasters used in story-telling, more built with water elements or super-fast launches.

"It's like filmmakers or musicians — whenever you have something that is built within the creative realm, people look at it and say, 'What can we do to make this bigger, better, more impressive,'" said Robb Alvey of ThemeParkReview.com.

Although no Florida coasters approach height or speed records, they do form a diverse group.

In four days, I had ridden 20 coasters and been turned upside down so many times I lost count. I had gone through basic vertical loops, diving loops, Immelmann loops, a pretzel loop and the world's only non-inverting loop; carousels, batwings, zero-gravity rolls, cobra rolls, simple corkscrews and interlocking corkscrews. My stomach had objected only once.

I considered this collection, representing some of engineering's most creative coaster designs. Then I got in line to ride Manta again.