Example: Starting with features and requirements
Let's next inspect EAST-ADL and its application using a small example: a Regenerative Braking System with ABS. A typical starting point for the development is features of the vehicle – as illustrated in Figure 2. Here the feature model of EAST-ADL defines the braking system under development by capturing the feature configuration and in particular shows some of the key braking related vehicle functionalities and their dependencies: for instance the optional AdvancedBraking feature is specialized by ABSBraking and by optional ESPBraking, but if ESPBraking feature is chosen also ABSBraking feature is then required. While this example shows just a few vehicle features, feature models can specify and manage the content of each vehicle in relation to the entire product line by addressing the features and their relationships such as in terms of feature dependency and exclusion. For the purpose of customization, market aspects such as models and markets can be organized in a feature model and traced to more technical features (e.g. the choices of particular hardware platforms).
In parallel to the composition of vehicle features, we may start with