Engineers, business managers, and governments are increasingly aware of the importance and difficulty of integrating technology and humans. The presence of technology can enhance human comfort, efficiency, and safety, but the absence of human factors analysis can lead to uncomfortable, inefficient, and unsafe systems. Systematic human-centered design requires a basic understanding of how humans generate and manage tasks. A very useful model of human behavior generation can be obtained by recognizing the task-specific role of mental models in not only guiding execution of skills but also managing initiation and termination of these skills. By identifying the human operator’s mental models and using them as templates for automating different tasks, we experimentally support the hypothesis that natural and safe interaction between human operator and automation is facilitated by this model-based human-centered approach. The design of adaptive cruise control (ACC) systems is used as a case study in the design of model-based task automation systems. Such designs include identifying ecologically appropriate perceptual states, identifying perceptual triggering events for managing transitions between skilled behaviors, and coordinating the actions of automation and operator.