Cascading Vehicle Attribute Requirements to Vehicle Systems

The vehicle attribute requirements are derived from customer needs, business needs, and government requirements enforced in the market where the vehicle will be sold and used. The vehicle attribute requirements are thus the highest level of requirements on the vehicle. These requirements are cascaded down (i.e., assigned to lower levels) to all lower level entities to ensure that the lower level systems within the vehicle are designed to perform their functions to meet the vehicle level attribute requirements. This chapter describes the requirements cascading process from the vehicle level to lower level entities and provides an example and considerations related to specifications of requirements on the vehicle braking system and its lower level subsystems.