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Last lane axis (i_te = n_lems)

Q Follow 5 Tl%

Figure A.6 — Calculation process of veiling luminance (part of /ті)

Figure A.7 — Calculation process of threshold increment/ті

Figure A.8 — Calculation process of edge illuminance ratio Rei

Figure A.9 — Subroutine for edge illuminance ratio evaluation

Annex В
(informative)

Extended r-table format for low mounting height luminaire

This extended format in tan e is needed when the mounting height of luminaires is very low (W < 2 m). In that case, the distance from the luminaires to certain points of the calculation grid is greater than 5H or even 12H and Table 3 cannot be used so that luminance at these points cannot be evaluated.

Table B.l is therefore extended in tan e up to 20 by 0,5 increment for every p angle (the number and values of p angles remain the same as those in Table 3).

Similarly to Table 3:

• all values are given for each combination of couple of angles (tan e; fi} but with a format of one decimal place;

• the values of these tables are also 10⁴ * r (tan e; p).

The shaded cells of the Table B.l show the possible extension from conventional measurements of samples of road surfaces in a photometric laboratory. It should be noted that measurements up to tan e = 20 become necessary when the mounting height of the light source if less than 1 m. In this last case the measurements are possible only on site, on a section of the road surface.

Table B.l — Angular intervals and directions to be used in collecting road surface reflection data in the case of extended r-tables used with very low mounting heights luminaires or car headlights