Travelwise: The human limits of roller coasters

According to the statistics, you are far more likely to die by lightning strike than in a roller coaster accident.

In the UK, the odds of being killed on an amusement ride are 300 million to one, whereas the odds of being killed by lightning are 10 million to one. In the US, around 1.7 billion rides are taken by nearly 300 million people each year, and from 1994 to 2004, the country reported an average of just four deaths per year. Comparatively, an average of 39 people die each year in the US from being struck by lightning.

Thanks to safety regulations and industry compliance, roller coasters manage to maintain a fairly sound safety record despite pushing the human body to exhilarating extremes.

The most extreme
The Formula Rossa in the Abu Dhabi theme park Ferrari World is the fastest roller coaster in the world, reaching speeds of 149mph. Aided by hydraulic power, it accelerates from 0 to 62mph in two seconds. Built by the Liechtenstein manufacturer Intamin, the ride’s track was modelled after the Italian racetrack Autodromo Nazionale Monza, located north of Milan, which hosts the Formula One Italian Grand Prix motor racing championship every year.

The roller coaster with the fastest acceleration is the Dodonpa in Japan’sFuji-Q Highland park. Using a jet-assisted compressed air launch,it goes from 0 to 107mph in 1.8 seconds. The tallest coaster, meanwhile, is the Kingda Ka at Six Flags Great Adventure in Jackson, New Jersey, featuring a 418ft drop.

On the horizon is a new source of adrenaline rush. Rather than trying to be the fastest or highest, the California design firm BRC Imagination Arts wants to make riders feel weightless for eight continuous seconds. The idea is to replicate what astronauts feel as they train for zero gravity conditions, which is why the proposed ride looks a lot like a spaceship. Named the Vomit Comet, after what astronauts have nicknamed the NASA KC-145A aircraft, the structure is fully enclosed and glides down a horizontal track, only to be whipped straight up along a vertical axis and then back down again. Though the ride has been designed, it has not yet been bought by a specific theme park.

But how much more thrilling could these rides technically get before they become life-threatening?

Taking it to the limit
The potential danger (and thrill) of this extreme activity is actually associated with acceleration, not speed. As acceleration occurs, gravitational (g) forces act on the body in different directions. The amount of g’s, how long they last and the direction in which they are felt all contribute to what the human body can tolerate. Fighter pilots, for instance, are trained to withstand around eight or nine g’s for relatively long periods of time, whereas the most extreme roller coasters typically give off between four and five g’s for about a tenth of a second at a time.

Rides undergo rigorous testing to comply with safety standards, explained Jim Seay, president of the US-based manufacturer Premier Rides and chairman of a committee on amusement rides safety for the global industrial standards group ASTM International. Premier Rides, which is currently working with Bollywood producer Manmohan Shetty to bring a massive high-end amusement park to the outskirts of Mumbai, has a new roller coaster opening at California’s Six Flags Discovery Kingdom calledSuperman Ultimate Flight, a ride launched by a magnetic propulsion system. “[Worldwide,] the actual engineering of the rides is very similar to the design approach you would see for commercial or military aircraft,” described Seay, who previously worked in the aerospace industry.

First, a rendering of a roller coaster goes through a round of virtual computer testing to determine if the structure can run properly under various configurations. Then, engineers from the theme park -- and sometimes government inspectors -- review the design. If they sign off on it, the ride is built in parts, using high-tech machines that can bend steel within millimetre accuracy, creating a structure nearly identical to the computer design. The many parts are then shipped to the theme park where the ride is installed. “It’s very much like a giant erector set,” said Seay. Engineers from the manufacturing company, engineers from the park and government inspectors carry out “acceptance testing” to ensure that the ride operates correctly and safely. After hundreds of test-runs, crash test dummies are strapped into the coaster and it goes through hundreds more cycles. If all is well, safety personnel from the manufacturer ride the coaster to make sure it is running as desired. At that point, ride operators and maintenance professionals are trained by the design company. Only then does the park start bringing in the public.

Playing it safe
Over the centuries, roller coasters have become both more exciting and safer. The first roller coasters may have been Russian ice slides built in the late 16th Century. Compare that with today’s ultra-sophisticated, ultra-precise, carefully-engineered coasters, which are bigger, faster and more death-defying (or at least marketed that way) than ever before. Regulations have also increased dramatically – especially considering that some countries, such as the US, had no regulations at all until the 1960s. 

Roller coaster regulation varies from country to country. For instance, in Singapore, the Building and Construction Authority, an agency of the federal Ministry of National Development, oversees amusement ride safety. In the US, on the other hand, the federal government only regulates rides at travelling carnivals and fairs, while state governments regulate stationary parks. Rules vary at the local level, too. Florida, home to Walt Disney World, for example, has state officials who inspect rides at theme parks with fewer than 1,000 employees, but the state relies on large parks like Disney World and Universal Studios to regulate themselves.

Globally, the nonprofit group ASTM International (formerly the American Society for Testing and Materials) sets voluntary safety standards for the industry regarding design, manufacturing, maintenance and operations. While many governments have adopted their own safety standards, the  on Amusement Ride Safety Even when states and countries have their own laws, the industry uses ASTM standards as an overarching roadmap . Twice a year, a group of engineers, park operators, regulators, consumer advocates and other experts from around the world meet to update and revise these standards.

Zip line attractions, for example, are beginning to emerge in theme parks throughout the world, said David Mandt, spokesman for the trade association the International Association of Amusement Parks and Attractions. Since previous standards had not addressed commercial zip lines in great detail, an ASTM International subcommittee is working ondeveloping a new standard for these kinds of rides.

Although amusement rides are relatively safe overall, individuals with heart conditions should not go on roller coasters, since they can speed up the heart rate and potentially lead to a cardiovascular event. Pregnant women are also advised against riding roller coasters. For healthy visitors, most theme parks post rider safety guidelines for roller coasters and other rides. (BBC)