Standards and Recommendations - Road Lighting: Fundamentals, Technology and Application - page 103

9.2.3 Lighting for Pedestrians and Low-Speed Traffic

The method of specifying lighting for these categories of road users is the same as
that used for the motorized traffic category dealt with in the previous Section. But,
needless to say, the criteria and lighting values specified are different. Just as for
motorized traffic, the lighting classes for pedestrians and cyclists, called P1-P7, are
obtained from a weighting-value table. The factors used in this table are largely the
same as those used by CIE, viz.:
• travel speed (ranging from low to walking speed),
• intensity of use (ranging from busy to quiet),
• traffic composition (from a combination of pedestrians, cyclists and motorized
traffic together to cyclists only),
• the presence, or otherwise, of parked vehicles,
• the ambient luminosity (from high to low),
• the need, or otherwise, for facial recognition.
The weighting values themselves differ slightly from those of CIE. Again, as in CIE,
the sum of all weighting values, VWS, determines the number of the lighting class
P according to:

= −

VWS .
The values specified for the average and minimum illuminance for the various P
classes are exactly the same as those specified by CIE (see Table 9.4 ).
An additional set of classes is defined to supplement the P classes for those cases
where the purpose of the lighting is to also reduce crime and suppress feelings of
insecurity. These additional classes are called SC classes, where SC stands for semi-
cylindrical, the illuminance measure used as the criterion for these classes. The
lighting values required for the SC classes range from 10 to 0.5 lx for the semi-
cylindrical illuminance. Another set of additional classes is defined for situations
where vertical surfaces need to be seen, as for example at street crossings. These types
of additional classes are called EV classes, where EV stands for vertical illuminance.
The SC and EV classes require considerably higher semi-cylindrical and vertical
illuminance values, respectively, than do the corresponding classes of CIE. The
range of minimum semi-cylindrical illuminance for the European SC classes goes
from 50 to 0.5 lx (CIE from 3 to 0.4 lx) and for vertical illuminance from 50 to 0.5 lx
(CIE from 5 to 0.6 lx). The European Standard does not give guidelines for the
selection of SC or EV classes. The Standard leaves this to national level for the
individual countries.
The European standard uses two different luminaire classification systems for
glare restriction, namely the luminous intensity “G” classification system and the
luminaire glare index “D” system (the latter taking the size of the bright area of
the luminaire into account, in addition to the luminous intensity). Both systems
are defined in Sect. 8.2.4. The lower the class number the higher the risk of glare or
obtrusive light. Such “low-class” luminaires can only be used where the surroundings
are bright and/or where a relatively large amount of glare can be tolerated.

P 6