4.3.6.2.
Information about the system principle II
System instructions should be correct and simple.
Explanation:
Design of user instructions is an HMI issue in itself. Instructions are typically ignored by drivers and this is exacerbated by poor design of the instructions. This principle is intended to promote high acceptance of instructions by drivers.
Instructions should be factually accurate in all important aspects. Each element of the instructions (group of words, diagram, function-described etc.) should be correct for the actual system to which it relates.
Simple has to be interpreted in the context of the system being described and will vary with the complexity and functionality of the system. The instructions should be unambiguous and easy to understand, if possible by all members of the intended user population (
e.g.
documents in ‘Plain Language’). Instructions should not be overly technical and should use user-oriented language. It is important that the instructions are simple even if the system is complex.
Examples:
Good
: Good examples might be expected to have some of the following features: well presented manual with factually accurate text and diagrams, contents page, page numbers, good use of colour, written in a plain language style using common words. Good Index. Use of different fonts, italics, bold, underlines etc. to distinguish portions of the text.
Bad
: Instructions which refer to a previous model with different functions and controls.
Applicability:
This principle applies to system instructions in all forms.
Verification/Applicable methods:
Assessment of correctness is a matter of comparison between the actual system and the system instructions. Assessment of simplicity is a matter of judgement taking driver knowledge and expectations into account.
A system instruction can conform with this principle even if small errors are present as long as these can be shown to be unimportant and are not too numerous.
Verification requires assessment and judgement.
4.3.6.3.
Information about the system principle III
System instructions should be in languages or forms designed to be understood by the intended group of drivers.
Explanation:
The aim of this principle is to ensure that instructions are of use to as many drivers as possible and that drivers are aware of the capabilities and limitations of the system, its context of use etc.
Different forms of instructions may exist which could be presented in different modalities: Auditory instructions may be spoken or presented by noises or earcons. Visually presented information includes diagrams, photographs, highlighting of the next element, programmed tutorials etc.
Spoken instructions and written instructions (either printed or within a system) will be in one or a number of languages (e.g. English, Finnish etc.)
This principle requires that when instructions are being devised, consideration is given to the intended and most likely driver population and that instructions are designed which can reasonably be expected to be understood and used by as many drivers as possible.
Manufacturers should consider the driver population and the likely and intended use of the system as well as the native languages and other languages spoken and read. Published statistics on language proficiency by country could be used as reference. At minimum, the majority language of the country in which the system is sold should be considered. Diagrams often provide additional clarity. Where used these should follow accepted stereotypes and conventions for the intended population.
Examples:
Good
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