Symbols – also referred to as icons - 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 symbols, however, have the potential to negatively affect safety (e.g., if the driver does not understand the symbol and either does not respond in a timely manner, or responds in a manner that makes things worse). Despite the ubiquity of symbols within the in-vehicle environment, few guidelines exist for testing of symbols. Key shortcomings of existing symbol testing procedures include: (1) a lack of contextual information provided to experimental participants, (2) over-reliance on evaluator judgment regarding how well an experimental participant comprehended a symbol’s meaning, and (3) a lack of prescriptive information - feedback to symbol designers regarding how individual symbols could be improved based on the results of the comprehension testing.
This update to the 2008 version of J2830 includes (1) references to ISO symbols testing guidelines, (2) more recent research in this area (e.g., Chi & Dewi, 2014; Huang, Shieh, & Chi, 2002), (3) research not considered in previous drafts (e.g., Zwaga, 1989 and Zwaga, 2000), (4) newer ways in which symbols are used in the in-vehicle environment (e.g., on mirror surfaces), and (5) references to other aspects of the symbol development procedure to aid the comprehension testing process and make it more likely to lead to easily-perceived and well-understood symbols.
Although the focus of this document is comprehension testing of in-vehicle symbols, there are a number of additional symbol design/evaluation procedures that provide great value to the overall process of developing effective symbols. Therefore, this recommended practice provides an overview of procedures for the production test (4.1.3.1) the appropriateness ranking test (4.1.3.2), and the matching test (4.5).