Advances in vehicle engineering resulted in substantial reduction of the natural retarding capability of trucks and tractor trailers. These trucks need help slowing down; therefore, the market demands improved performance from vehicle retarders.Today's heavy-duty vehicles: Are aerodynamically designed to slip through the air Roll on advanced radial tires GVW or GCW has increased Engines and equipment are more efficient with reduced factional losses. Improved and new Jake Brake® retarding concepts have been developed. In addition to the standard Jake Brake retarders for unit injector and PLN engines, combination of Jake Brake retarders with exhaust brakes and optimized injector cam operated Jake Brake retarder, a new technology high performance Jake Brake retarder for PLN engines has been developed and introduced on the market. Further refinements of the existing concepts and development of new processes, including a twocycle compression release process for the four-cycle engine, will further enhance the Jake Brake retarder performance in the future.