Have you ever been on a roller coaster and spotted a sign reading “keep arms and legs
inside of the train”?
Then, you look up and see people putting their hands up in the air as they scream down the
ride's first drop?
Yeah me too.
Surely the signs can’t be right if so many people ignore them.
Well, yes but also no.
For some roller coasters around the world, you shouldn’t put your hands up, whilst
for others, you can wave them around as much as you like - but why?
The answer has to do with the space surrounding a roller coaster, or rather, the lack of.
Today, designers of amusement riders create clearance envelopes on their rides, a buffer
of empty space which surrounds a roller coaster’s train, making it impossible for people to
touch things as they go around the ride.
Accidentally coming in contact with a part of the ride whilst travelling at high speed
does not sound pleasant, or safe.
However, the idea of putting a specific amount of space between riders and their surroundings
is actually relatively new when it comes to thrill rides.
On older roller coasters, especially ones built in the early 1900s, safety was much
less of a concern.
The designs of older wooden roller coasters didn’t need to include space between guests
and their surroundings simply because rides weren’t that fast.
Back in the day rides were much less thrilling than the ones we have today.
Roller Coasters originally featured no form of restraint, instead, guests were simply
instructed to hold on to the bar in front of them throughout the ride.
Perhaps because of this, early riders of roller coasters didn’t have time to put their hands
up in the air.
Although it wasn’t long before rides became taller, faster, and more intense.
By the 1970s a growing number of roller coasters were being made out of steel, instead of wood.
This meant ride designers could incorporate larger and more thrilling elements with the
hopes of attracting even more guests.
During this time of innovation, the safety of roller coasters drastically improved too.
New technology allowed them to operate more safely and efficiently than ever before.
Manufacturers of roller coasters also began to consider clearance envelopes, ensuring
that riders wouldn’t be able to touch anything whilst on these high speed rides.
Often the trains themselves were designed to limit how far riders could reach.
By the late 1970s roller coasters began to go upside down, and with this development,
the over the shoulder restraint became more popular.
This type of harness severely limited the upper body movement of riders, restricting
how far they could reach.
The trains of looping roller coasters often also featured deep sides which further restricted
the movement of riders arms and legs - like the ones found on Loch Ness Monster at Busch
Garden Williamsburg.
Some older rides saw their trains changed or altered to limit movement and create a
safe clearance envelope.
Side panels can be found on the trains of some wooden roller coasters, such as American
Eagle at Six Flags Great America, which prevent riders from reaching outside of the car.
All of these designs enclosed guests within the trains, minimising their ability to move,
and likely impacting rider comfort.
In other cases, parts of the ride have been redesigned to ensure riders are safe.
Millennium Force at Cedar Point, and several other roller coasters, feature supports with
grooves cut out of them - a quick fix to create an appropriate clearance envelope.
Since the 1970s, roller coasters have come a long way.
Rides are taller, faster, and more intense than ever.
On top of this, the type of restraint used on roller coasters have changed too.
To enhance rider comfort, and provide a more thrilling experience, modern rides often feature
smaller lap bar restraints.
These hold riders in through a harness which rests over their laps, as seen on VelociCoaster
at Universal's Islands of Adventure.
These restraints allow guests to move their upper body during the ride, ultimately increasing
their ability to reach elements surrounding the roller coaster’s track.
On top of this, many manufacturers of roller coasters have begun to create more open train
designs.
These expose riders to the elements, making them less protected against wind and placing
them closer to their surroundings.
As a result of this, modern roller coasters have had to embrace strict clearance envelopes,
ones that protect all riders on board.
Though, many roller coasters manufacturers already understood that if their rides hurt
riders, parks would be reluctant to buy their products.
However, in 2004, American Society of Testing and Materials published a standard for ride
design, including specific requirements for clearance envelopes.
They stated that an additional 3 inches, or 76.2mm, is required beyond the maximum reach
of guests on the ride.
This distance provides a margin of error, leaving riders unable to contact any object,
keeping them safe.
But how do they calculate the maximum reach of guests?
For this, human anthropometry, the study of the measurements of the human body, is utilised.
The measurements of the demographic of the riders able to ride the attraction is used.
For many larger roller coasters, this is likely to be an adult male within the 95th percentile
- meaning their reach is larger than 95% of the population.
Clearance envelopes are unique to each ride as roller coasters are built for different
target audiences, using a range of train designs, matched with a variety of restraint types.
Because of this, some manufacturers of roller coasters conduct pull-through tests upon construction.
During this, a clearance envelope, often depicted by a metal or wooden frame, is attached to
the ride’s train, which is then slowly pulled through the roller coaster’s track.
As this occurs, engineers check the envelope doesn’t contact the ride’s track, supports,
or any items in the general vicinity.
Only once the pull through is complete can the roller coaster begin to test at full speed.
The thought of being able to touch something whilst on a roller coaster is a scary one.
So scary that designers of rides purposely create the illusion that guests could collide
with part of the ride to enhance the thrill level.
Today, many rides feature near-miss elements, parts of a roller coaster which cause guests
to pass nearby objects.
Many rides use tunnels, to create a ‘head-chopper’ moment, a feeling that you might hit your
head as you fly through.
Other rides, like Fury 325 at Carowinds, employ the same effect by suddenly dipping under
another part of the ride’s track or support structure.
Roller coasters that place guests below the track can provide guests with the opposite
sensation, foot-choppers.
Inverted rides may dip close to the ground to give riders the feeling they might hit
their legs instead.
Nemesis at Alton Towers is the perfect example, which places guests between rocky terrain.
Other types of roller coasters have become notable for offering multiple near miss elements
as part of the ride experience.
The wing coaster sits guests over the sides of the track and has a thin, but wide profile.
This allows the trains to slot through billboards, in between structures like on Gatekeeper at
Cedar Point, or even through the ride’s own supports.
With all modern near-miss elements the clearance envelope is considered, so you don’t need
to duck to protect your head, but you can if you want to.
In some cases however, the clearance envelope of a ride is smaller than the ideal demographic
of riders.
When this happens, manufacturers of roller coasters often employ maximum height requirements,
restricting guests over a certain height from riding.
This protects those with larger reaches from accidentally breaching the clearance envelope
if they were to ride.
Many of these maximum height requirements measure close to 2m, or 6ft 6 inches - meaning
they’re not applicable for most of the population.
Although Steel Dragon 2000 at Nagashima Spa Land has a height restriction of just 6ft
1.83m - the world’s longest roller coaster seemingly doesn’t like tall people.
So there you go, now you know that you safely put your hands up on modern roller coasters
without touching anything.
Well unless the ride is quite old and tells you not to, or you’re quite tall and you
can’t ride.
Thank you for watching and we’ll see you all next time.