Document ID: chunk:federal_register_of_legislation:F2018L01521:reg:22:p5
Version: federal_register_of_legislation:F2018L01521
Segment Type: reg
Provision Reference: reg 22 (pt 5/6)
Character Range: 44808–47535

measurement. The method of achieving this is set out in Figure 6 of the Appendix to this annex, the reference plane being a hard, flat, level surface upon which the vehicle stands, and which has two measuring scales firmly fixed to its surface; these shall be graduated in millimetres, the X-X scale being not less than eight metres long and the Y-Y scale not less than four metres long. The two scales shall be set at right angles to each other as shown in Figure 6 of the Appendix to this annex. The intersection of these scales is the ground zero.
3. Examination of the reference plane
 In order to provide for minor variations in the level of the reference plane or test area, it will be necessary to measure the deviations from ground zero along both the X and Y scales at intervals of 250 mm and to record the readings obtained so that corrections can be made when checking the vehicle.
4. Actual test attitude
In order to provide for minor changes in suspension height, etc., it will be necessary to have available a means of bringing the reference marks to the correct coordinate positions relative to the design attitude before further measurements are taken. In addition, it shall be possible to make minor lateral and/or longitudinal adjustments of the vehicle's position so as to place it accurately in relation to the reference grid.
5. Results
The vehicle having been correctly placed relative to the reference grid and in its design attitude, the site of the necessary points for studying the forward visibility requirements can be readily determined.
Test methods to determine these requirements may include the use of theodolites, light sources or shadow devices, or any other method, which can be shown to give equivalent results.
Annex 4 – Appendix

Figure 1

Determination of V points

       (1) Line tracing the median longitudinal plane of the vehicle.
       (2) Line tracing the vertical plane passing through R.
       (3) Line tracing the vertical plane passing through V1 and V2.

Figure 2

Observation points of the "A" pillars

Figure 3

Angles of obstruction

Figure 4

Evaluation of obstructions in the 180° forward direct field of vision of the driver

Figure 5

Dimensional diagram showing relative positions of E points and P points

Figure 6

Level work place

Figure 7

Definition of the area "S"

(paragraph 5.1.3.2. of this Regulation)

*The category code may also be in the format L1, L2, L3 etc
[**]See clause 3.1
     [*] Former titles of the Agreement:
 Agreement concerning the Adoption of Uniform Conditions of Approval and Reciprocal Recognition of Approval for Motor Vehicle Equipment and Parts, done at Geneva on 20 March 1958 (original version);
 Agreement