Permanent magnet (PM) eddy current brakes are a simple and reliable alternative to mechanical, pneumatic or electromagnetic brakes in transportation applications. This paper outlines research that addresses the design of these braking devices, which can be utilized in vehicles, elevators, and moving machinery of all sorts. Results from a high-speed rotating test fixture were used to develop a set of magnetic scaling laws for the sizing and cost analyses of the brakes. Using these results, a full-scale brake was designed for a roller coaster application. Good agreement is found between the experimental results from the test fixture and analytical results based on electrodynamic theory.