The overall goal of this SAE Information Report is to provide designer recommendations for In-Vehicle Alphanumeric Messages. Our first objective is to summarize the relevant literature regarding the most efficient presentation, content, and interaction for alphanumeric information on in-vehicle displays. These recommendations provide procedures, heuristics, and principles for the development of alphanumeric message display.
A key issue in the development of human factors design recommendations for alphanumeric message design has been the availability of relevant findings from the research literature. The applicable research that provides a strong rationale for design decisions was captured. To this end, a theoretical framework and a set of design parameters that addresses the most important issues associated with an in-vehicle alphanumeric display is provided. A set of specific design recommendations with supporting rationale from the published literature is also described. As with Campbell et al. (1996), the development of human factors design recommendations should be clear, relevant, and useful and ultimately requires a judicious mix of science and art. That is, while a number of empirical and systematic methods are available for the development of design recommendations, the final recommendations will always represent an integration of user requirements, design constraints, available information, and expert judgment (Carney et al., 1998).
Ultimately, this Information Report is structured so that the recommendation can be entered at any point. While reading the entire Information Report will help designers understand the overall picture with regard to alphanumeric display design in general, entry from different starting points and perspectives is possible. For example, some designers may be focused on a particular product (e.g., Navigation aid) or a particular message characteristic (e.g., long messages with more than 20 words) or a particular display feature (e.g., acceptable scrolling speed of a dot matrix display). Beyond this general organization, each guideline is kept in a simple format to convey information in a succinct manner.
To focus on the most relevant information related to in-vehicle alphanumeric presentation, reports/research that focus on driver performance characteristics related to in-vehicle systems design were systematically selected. One area that is particularly applicable to in-vehicle alphanumeric messages is the literature pertaining to the design of Dynamic Message Signs (DMS), also commonly referred to as Variable Message Signs (VMS) or Changeable Message Signs (CMS). Because DMS/CMS/VMS display real-time traffic information, many of the fundamental issues associated with these devices are similar to those of in-vehicle alphanumeric messaging. Therefore, the use of recommendations from this domain can be useful in framing the context of in-vehicle messages.
Design recommendations from a number of governmental and industry recommendations were also included. There are several design recommendations that are directly applicable. Most notably are a set of in-vehicle information system interface design recommendations from the FHWA by Campbell et al. (1998) and Lee et al. (1999). While they do not necessarily address the specific goals of this Information Report, they provide a comprehensive set of recommendations with a structure and method for the overall design of in-vehicle information systems. In addition, the European HARDIE recommendations, ISO, SAE, AAM and other recommendations where appropriate were included. No single report can answer the questions for this Information Report, however, together they provide support for many of the design recommendations made.