In order to achieve robust and reliable vehicle control system designs, it is important to follow strict testing methods. Most engineers are familiar with test requirements for individual components and devices used in a vehicle control system. Not only do the individual components need to be validated, but also the summation of all elements, including the system's software. There must exist specifications and testing requirements for the entire integrated system. The testing must be designed to validate the entire vehicle control system, so that it can deliver its intended function under a variety of operating environments, conditions and applications.System performance may be influenced by all of the other systems on the vehicle, such as type of: engine, transmission, foundation brakes, air systems, suspension, and retardation. While it is not possible to replicate all operating environments it is important to follow a plan which can effectively validate the system.The purpose of this paper is to discuss the need for having a properly designed validation process, examine methods of determining functional requirements, and review the validation process for an antilock braking system with automatic traction control (ABS/ATC).