This standard specifies the requirements and measurement methods for 180° forward visibility for drivers.
This standard is applicable to Category M1 motor vehicles.
2 Normative references
The following referenced documents are indispensable for the application of this document. For dated references, only the edition cited applies. For undated references, the latest edition of the referenced document (including any amendments) applies.
GB 11555-2009 Motor vehicles - Windshield demisting and defrosting systems - Performance requirements and test methods
3 Terms and definitions
For the purposes of this document, the following term and definition apply.
3.1
vehicle type with regard to the field of vision
a category of motor vehicles which do not differ in the following essential respects:
——the external and internal forms and arrangements within 180° forward visibility for drivers, which may affect visibility;
——the shape and dimensions of the windscreen and its mounting.
3.2
three-dimensional reference grid
a reference system which consists of three orthogonal reference planes (see Figure B.1). The three orthogonal reference planes are:
X reference plane——the vertical plane perpendicular to the Y reference plane, usually passing through the centers of the left and right front wheels;
Y reference plane——the longitudinal symmetrical plane of motor vehicle;
Z reference plane——the horizontal plane perpendicular to the Y and X reference planes.
