Standards and Recommendations - Road Lighting: Fundamentals, Technology and Application - page 102

For the lighting of the immediate surrounds of the carriageway the European
standard uses the parameter EIR instead of SR (as already defined in Sect. 8.1.3.).
The EIR range is from 0.35 to 0.30.
Which lighting class is applicable in a given situation is specified in draft CEN/TR
13201-1 “Road Lighting—Part 1: Guidelines on selection of lighting classes” (CEN
2013a ). Here, too, the European system follows the system of the CIE described in the
Section above. Which lighting class is applicable in a certain situation is dependent
on the following factors:

• the difficulty of the geometry of the road in terms of whether there is separation

of carriageways and intersection density,

• the traffic characteristics in terms of speed, traffic volume, traffic composition,

possibility of there being parked vehicles,

• the average brightness of the area (ambient luminance),

• the difficulty of the navigational task.

To determine the lighting class applicable according to these factors, different weight-
ing values, V w , are given—just as in the CIE Publication. The factors used are largely
the same as those used by CIE (see Table 9.2 ). Again, as in CIE, the sum of all
weighting values, VWS, determines the number of lighting class M according to:

M = 6 − VWS .

9.2.2 Lighting of Conflict Areas

For the lighting of conflict areas on traffic routes, where different vehicle streams
intersect, where there is a change in road geometry (e.g. reduced number of lanes), or
where the same road network is used by a mixture of motorized traffic and other types
of traffic (pedestrians, cyclists, etc.), the draft European Standard (again as in CIE)
uses weighting values to determine the lighting class of the conflict area (C0-C5)
(CEN 2013a ). The corresponding lighting required for each conflict lighting class,
C, is specified in terms of the familiar lighting criteria for level, uniformity, glare
restriction and surround lighting (CEN b ).
For pedestrian crossings a quantitative specification is not given. It is stated that
the intention of specific pedestrian-crossing lighting is to illuminate the pedestrians
themselves and to draw the attention of motorists to the presence of the crossing.
The draft states that illuminance on a vertical plane should therefore be signifi-
cantly higher than the horizontal illuminance at the crossing. Zones at either end of
the crossing, where pedestrians wait to enter the crossing, should receive adequate
illumination.