This document describes a process for testing the comprehension of symbols or icons. Although the process may be used to test any symbols or icons, it has been developed specifically for testing ITS active safety symbols or icons (e.g., collision avoidance), or other symbols or icons that reflect some in-vehicle ITS message or function (e.g., navigation, motorist services, infotainment). Within the process, well-defined criteria are used to identify the extent to which the perceived meaning matches the intended meaning for a representative sample of drivers. Though the process described below reflects a paper-and-pencil approach to conducting the testing, electronic means (i.e., conducted using a computer) can be used as well. The data or results from this process are analyzed to assess the drivers' comprehension of the symbol or icon. These data will be used to provide guidance in the design of in-vehicle symbols or icons.
Icons and symbols can be used to communicate information to the driver in a manner that is not dependent on language and can save valuable space on in-vehicle displays. Incomprehensible icons, however, have the potential to negatively affect safety (e.g., if the driver does not understand the icon). Despite the ubiquity of icons and symbols within the in-vehicle environment, few guidelines exist for testing of icons and symbols. Key shortcomings of existing icon testing procedures include: a lack of contextual information provided to experimental subjects, over-reliance on evaluator judgment regarding how well an experimental subject comprehended an icon's meaning, and a lack of prescriptive information - feedback to icons designers regarding how individual icons could be improved based on the results of comprehension testing.