ingineria iluminatului - Journal of Lighting Engineering - Prof. Florin ...

Influence of the road surface on the efficiency of the street lighting installations
value of the specular factor S1. By
accepting a certain tolerance, it is possible
to characterize all road surfaces by a few
classes and one class by only one reflection
table typical for that particular class. In
other words, each class can be given by a
standard reflection table, to be used for
luminance calculations for any surface
belonging to that class. Of course, the fewer
classes a system has, the more practical it
will be to work with. The more classes a
system has, on the other hand, the more
accurate can be the results obtained with it.
In order to obtain a standardization in the
information for the calculation performance
data, a set of road surface standards R1, R2,
R3 and R4 is in common use.
In the case of reflection characteristics
S1 and Q0 can not be measured, an
approximate designation of the standard R
class can be made as in Table 1.
Table 1 Approximate designation of road surfaces into R road classes (according to Table 6 – CIE 30.2)
Class Description
Asphaltic road surface with at least 15% of artificial brightener (Grenette,
Luxovite, Synopal or similar) or with at least 30% of very bright anorthosites
(Arclyte, Labradorite or similar).
R1 Surface dressings with chippings where over 80% of the road surface is
covered and where the chippings exist for a great deal of artificial brighteners
or for 100% of very bright anorthosites.
Concrete road surface
Surface dressings with harsh texture and with normal aggregates
Asphaltic surface with 10% to 15% of artificial brighteners in the mixture
R2 Coarse and harsh asphaltic concrete rich in grave land with gravel sizes up to or
greater than 10 mm.
Mastic asphalt (Gussasphalt) after dressing in new condition.
Asphaltic concrete (cold asphalt, mastic asphalt) with gravel sizes up to 100 mm
R3 but with harsh texture (sand paper).
Surface dressings with coarse texture but polished.
Mastic asphalt (Gussasphalt) after some months of use.
R4
Road surface with rather smooth or polished texture.
The road surface belonging to R class
are more often used in lighting calculations
in Romania. Therefore I thought it would
be useful to make an evaluation of the
influence of these types of road surfaces on
the efficiency of lighting installations.
Considering the R classification system,
R1 table corresponds to the most diffuse
surfaces, R4 table to the smoothest
surfaces, and the fact becomes visible when
analyzing equivalent value curves-r – “iso-r”
diagrams – as seen in Figure 1. The
difference in form of the four diagrams is
obvious. The smoothest the surface is, the
slim “izo-r” diagram is.
Ingineria Iluminatului 2010; 12, 2: 33-44 35