ORLANDO, Fla. -- Fans of roller coasters that launch like rockets, gravity-smashing spin rides and water park splashes are in for a treat this year.

After a few years of belt-tightening, theme and amusement park owners have spent big bucks improving their attractions following their strongest attendance period last year since the 2001 terrorist attacks slowed the $10.8 billion industry's momentum.

"The purse strings have been loosened a bit, and that is an indication that the parks are anticipating folks to come and maybe spend their money more freely despite the price of gas," said Arthur Levine, theme park guide for the New York Times Co.-owned Web site About.Com.

Parks nationwide have spent an estimated $750 million on new rides and upgrades for this year, a vast increase over the $500 million spent last year, said Dennis Spiegel, president of International Theme Park Services Inc., a consulting group based in Cincinnati.

Alone, Six Flags Inc., the world's largest regional theme park company with 30 parks in North America, has spent $135 million on new attractions, nearly twice what it spent last year, in an effort to reverse an attendance slide from the previous year.

New rides are especially important for attracting visitors in a mature amusement park market like the United States, whose growth peaked in the late 1980s and early 1990s and then dipped after the terrorist attacks, Spiegel said.

For starters, several regional parks are introducing rides that approach the technological and storytelling sophistication found at major destination parks in Orlando such as Walt Disney World and Universal Orlando.

Notable examples include The Italian Job Stunt Track ride opening at Paramount's Kings Island near Cincinnati and Paramount's Canada Wonderland; Curse of DarKastle at Busch Gardens in Williamsburg, Va.; and PowderKeg at Silver Dollar City in Branson, Mo., Levine said.

The Italian Job, a fast-track coaster themed to the movie starring Mark Wahlberg and Charlize Theron, puts riders in vehicles tricked out as Mini Coopers and simulates a chase involving helicopters, explosions and a ride down stairs. Curse of DarKastle is a dark ride that recreates a scary Bavarian castle by using 3-D computer-generated imagery and fog and cold-air special effects that fans of The Amazing Adventure of Spider-Man at Islands of Adventure in Orlando will find familiar. PowderKeg is a coaster themed to a black powder mill in the Ozarks.

"These are regional and seasonal theme parks, but the technology has kind of trickled down," he said. "I applaud them for stepping up to the plate and investing some big dollars and putting some high-end rides that are really attracting a lot of attention."

The most anticipated ride of the season had trouble lifting off. Kingda Ka at Six Flags Great Adventure in Jackson, N.J., is claiming the title of the tallest and fastest roller coaster at 456 feet in height and launching passengers horizontally from 0 mph to 128 mph in 3 1/2 seconds. But the ride's opening was delayed from April to May 19 because of the need for additional testing.

"It's just so sophisticated. You're launching 20 tons at 100 plus miles an hour, climbing 450 feet, and you have to be able to stop it within inches," Spiegel said. "It just creates a lot of initial operation problems to work out," Spiegel said.

Spiegel wondered if the estimated $20 million-plus cost of the ride was worth the trouble.

"This isn't one where you just flip the switch and it goes on and it take off," he said. "It takes a lot of support to make sure that coaster is running, and as of yet they still haven't got that down."