All of the major sections of this dissertation were refined and published as other articles. However, this version has some unique information. Section 1.4.1 gives some ideas for extending my categorization of interruption types based on the cognitive state of the tasks. In most cases, the driving task would be "internally backgrounded", while information tasks would be suspended or "externally backgrounded". The empirical study is very relevant, since it involves a highly visual, time-sensitive, and continuous main task and a visual secondary task which obscures information used in the main task. If attempting to replicate the study, this version should be consulted along with the HCI article (McFarlane 2002). The HCI version is a better source in general thanks to an expanded discussion of results and revised text. The results highlight the complexity of the design question and the need to clearly prioritize which aspects of driving behavior we wish to support. There are many tradeoffs between different performance measures depending on the interruption management strategy used. The final remarks are poignant:
... Systems designers are not usually
interested in speculation. In the absence of real design guidelines that are accepted as standards
in the industry, systems designers will rely on their own abilities to engineer creative
solutions to the user-interruption problem. Design failure will be both likely, because of the
complexity and sensitivity of the problem, and costly.