Functional Specifications of Multilevel Highway

People reason hierarchically when they navigate highway networks. The hierarchical structure is induced by a sequence of tasks starting with route planning, continuing with wayfinding instructions, and leading to the actual driving process. In order to perform adequately, people need to map highway features and navigation actions from one task level to the next. What exactly are these features, actions, and mappings? To answer this question, the paper uses a formal algebraic model developed in the functional language Haskell. It defines an inheritance hierarchy for objects and operations in highway navigation. The results represent a case study for the support of modeling and software engineering processes in non-trivial applications through functional language specifications.