Roller Coaster Tycoon Ride Ratings IRL

Do you remember playing Roller Coaster Tycoon, the famous amusement park simulation game that shattered sales records and that remains one of the most beloved computer games of all time? I do, and I also remember the most important part of building any roller coaster in the game – testing. While it may seem mundane to someone who has never played, testing was how you figured out if your ride was going to make any money. The game would give your ride a score in three categories- excitement, intensity, and nausea. The goal was to maximize excitement, keep intensity reasonable, and keep nausea minimal. Largely this score was determined by the g-forces your ride produced. High g-forces could mean high excitement or it could mean people are too afraid to go on your ride. These ratings each varied from ‘low’ to ‘ultra-extreme’- both being scores you generally wanted to avoid. ‘Medium’ and ‘High’ were the sweet spot (except for nausea of course, which you always wanted ‘low’) and if you started to edge into ‘Very-high’ intensity you would start to see a drop in ridership, and thus revenue.

G-force relates the acceleration produced by something to the gravitational pull of the Earth. Most roller coasters pull at most 5G’s, or 5 times Earth’s gravity. They only do this briefly though- on big hills or tight turns. The Space Shuttle, for example, pulled 3Gs on reentry and sustained them longer – amusement park goers are clearly not astronauts! Big drops, lots of inversions, intense helixes, and lots of air-time (or negative Gs, where you feel like you are floating out of your seat) are what sell big rides. While real coaster designers don’t use the Roller Coaster Tycoon rating system to determine if their ride is any good they surely have the same design philosophy- be exciting, be intense but not too intense, and make sure the poor teenagers running the thing aren’t scrubbing vomit off the seat every time people get off. I hypothesized most rides, if they were in the game, would probably fall in the ‘Medium’ to ‘High’ intensity and excitement scores. Fortunately we now all carry around an accelerometer in our pockets built right into our smart phones so we can find out for ourselves!

This diagram shows how the accelerometer maps to the G’s measured by the Roller Coaster Test Meter.

The above diagram shows the axes I chose so that your phone could measure acceleration while resting safely in a zipped or sealed pocket while you rode a roller coaster. Vertical Gs are along your phone’s x-axis while lateral G’s are measured along your phone’s z-axis. This assumes that you put your phone into your pocket with your screen facing to your left and top-first, by convention.

The game’s formulas for computing the ratings for each ride were somewhat mysterious until the OpenRCT2 project published their open-source code and formulas. We knew for years that primarily the g-forces the ride produced made up the bulk of the score, and other features like theming, dueling trains, and music among other things also contributed. There are also unique multipliers for each ride that come into play.

I am simply trying to build a toy however that you can turn on, throw in a pocket, and share with your friends so I avoided the design route of asking you a whole survey about the ride’s features before you get on. Instead I went a different route to produce a set of formulas that roughly approximate that in the game regardless of what kind of roller coaster you are on, mystery multiples and all, by comparing the scores of real roller coasters to those in the game. Fortunately this summer I have had access to a roller coaster that was in the game and that I could ride in real life- a ‘boomerang’! These roller coasters are everywhere, as they have a small footprint and low cost that makes them perfect for parks wanting to add a coaster on a small budget. The model in the game is ‘Defibrillator’ and it can be found in the ‘Funtopia’ scenario of the original game.

So, readers, I rode it just for you! Just kidding- I am obsessed with roller coasters and the fact that I needed to ride one to complete this project was no coincidence. I started building a prototype of my app using Ionic and Apache Cordova, which would enable me to release my app for you on either Android or iOS without needing to rewrite any of my code. There are excellent tools for making a fun UI (I tried to keep the colors and theming true to the original game) and you can import great packages for social sharing and interfacing with the accelerometer. I ran my app and saved the base score using the basic formulas from OpenRCT2 with no multiples. I then tested for the scores for ‘Defibrillator’ in the game, computed my multiples empirically to scale my ratings appropriately, and voila! We now get scores we would expect if real coasters were in the game!

My Boomerang test ride with raw (unscaled) scores reported at the bottom.

Additionally I wanted to provide you with the raw data that went into your scores, just like the game. I used the awesome Chart.js library to plot the vertical and lateral G-forces live for you right on the screen, letting you have a nice plot of the forces experienced on the ride once you’re done:


Here are a few scores from my recent trip to Cedar Point and Kings Island in Ohio:

It is amazing fun- my favorite highlights are the legendary The Beast having an appropriate intensity of ‘Very-high’ and the crowd-favorite Maverick having excitement at ‘Very-high’. I even rode the new Steel Vengeance– just look at those vertical G’s! Simply download the app from Google Play or Apple App Store, insert the phone top-first and screen facing left into a pocket, and hang on tight! Obviously follow any rules about loose articles (they are there for a reason) but generally as long as you have a pocket that can be sealed this is a fun way to rate coasters, plot their g-forces, and brag to your friends about how you pulled 5G’s on Steel Vengeance this summer. Once you hit the ‘end’ button hit ‘share’ and post the scores to social media, then hit ‘clear’ and enter the next coaster’s name before going and conquering it. Have fun and make good choices!

Download on Google Play

Download on the Apple App Store

American Roller Coaster Trivia Alexa Skill

If you just want to add the game to your Alexa device, click here!


Sometimes the problem I am trying to solve isn’t something practical like a new educational game or 3D printed gadget. This time, the problem I was trying to solve is that I wanted a t-shirt. Amazon has monthly offers for swag if you develop skills for their Amazon Alexa product, which are basically like the platform’s “apps”. They let you have the digital assistant perform all sorts of tasks, like turn on and off your smart devices or interface with your favorite websites. You can also make Alexa play games with you, which is what I decided to do.

It’s no mystery from my website that I love roller coasters, so I decided that what Alexa really needed was a roller coaster trivia skill. This would let me get my feet wet into how Alexa development works and let me produce a fun game to share with my fellow roller coaster enthusiasts. The idea is that it will take a number of questions I have written about the best roller coasters in America, like what years rides opened, what park they are at, how fast they go, and more. Alexa asks five of these questions at random and keeps track of your score. Here’s some sample questions:

Name this roller coaster model who’s namesake was used by Aboriginal Australians for hunting. (Answer: Boomerang)

The oldest roller coaster in America is what? (Answer: Leap-the-Dips)


I was happy to discover that I could write Alexa skills using one of my favorite languages, Node.js, and that I could set them up on one of my favorite platforms, Lambda, which is part of Amazon Web Services. Essentially you can develop an Alexa skill like you would any microservice. Of course, there are rules that you have to follow that you can learn from one of their many samples, which is where I found an excellent sample for a trivia game. My coaster trivia uses this code extensively, and let me see a fully functioning Alexa skill that follows the best practices. I discovered all sorts of things- building responses, handling requests, and what Alexa has trouble saying. When you go to publish your Alexa skill you get a nice interface to test what you’ve done, which is where I found out that some roller coasters have names that do not play well with Alexa’s speech technology. I found, for example, that the roller coaster Rougarou is very hard to understand, so my questions related to it had to be dropped. If you are at all interested in making your own skills for Alexa, I recommend starting with one of their samples. It walks you through the whole process, from getting started with Lambda to creating intent schemas and testing.


I made all of my code public by forking the original Amazon sample. You can get it here!

I really like the Alexa platform and have many more skills in development. I have a lot of plans as to how digital assistants may be valuable in the classroom. You can keep posted on my projects here, or on my new Alexa Skills page I linked from my Projects page.

Finally, you can add the skill to your Alexa device by clicking here, or search American Coaster Trivia in your Alexa app!