25. The expert from Poland, in his capacity of Chair of the Informal Working Group on Visibility, Glare and Levelling (IWG VGL), briefed GRE on the IWG activities (GRE-78-36). He introduced a proposal and justification for a new diagram that defines the limits of a new aiming range for the dipped-beam headlamp (GRE-78-23-Rev.1) by lines. He also proposed to delete the 2,000 lm criterion (GRE-78-32).

26. For line 1, GRE generally agreed to a move to the right to the 0.2 per cent mark. Several experts also agreed that this shift should correspond with a shift of line 4 to retain the 1.6 per cent tolerance. The experts from Poland and UK pointed out the need for additional justification of tolerances for moving line 4, and invited OICA to provide the necessary details. Based on the GRE considerations, the experts from Italy, Netherlands, UK and OICA offered to prepare an amendment proposal for consideration at the next session.

29. The expert from Poland provided a summary of initial aiming and levelling tolerance issue (GRE-79-23, GRE-79-24). The experts from Italy and the Netherlands briefly introduced GRE-79-29 as a discussion paper for the possible introduction of new requirements for headlamp levelling, in particular on the vertical inclination in relation to the dipped-beam headlamp mounting height. GRE agreed to keep GRE-79-29 as a reference document for the next session.