This European Standard gives design rules and guidance in order to ensure proper visibility, luminance and contrast of screens, controls and indicators in the cab in all operating conditions (day, night, natural or artificial incidental lighting). It covers three aspects: necessary characteristics of the displays, controls and indicators in order to ensure proper visibility: range of luminance and contrast, and possibility of adjustment of perceived brightness; rules for positioning of the displays, keyboards, controls and indicators in the cab and on the driver's desk: position, angle of visibility, etc. with consideration of the normal driving position and of the working environment (windscreen, natural or artificial lighting in the cab, unwanted glare and reflections, etc.); design of symbols. There are objectives, recommendations and normative requirements as follows: a) Objectives Objectives are labelled by the term "objective" and are expressed by "should". Objectives themselves are not subject of assessments, Objectives provided by this standard are deemed to be fulfilled by the application of this standard. b) Recommendations Recommendations are expressed by "should". A recommendation is only subject of assessment if the recommendation is chosen by the applicant. c) Normative requirements Normative requirements are expressed by "shall" and represent the comprehensive set of interoperable requirements. They are subject to assessment. NOTE Assessment is a process of validation performed by an assessor, e. g. a notified body or a quality inspector. If a requirement contains an option, the choice of this option is purely up to the applicant. Where reference to a country is given this refers to internal traffic within that geographical area only.