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

W van BOMMEL
lighting should therefore automatically
adapt itself to those circumstances.
Measuring devices for circumstances like
weather, traffic density, composition of
traffic, traffic flow are readily available
today and can be easily applied. Intelligent
lighting driven by these sensors can
significantly contribute to costs and energy
savings. LEDs that simple can be regulated
between 0 and 100% light output will
accelerate putting these intelligent systems
into use. In draft CIE Publication Nr. 115
(2nd edition) socalled weighting factors are
defined that indicate under which
circumstances road lighting levels can be
reduced with one or more classes. Table 1
shows the main table from that draft
publication.
Table 1 Parameters and weighing factors for the selection of lighting classes for lighting in residential areas
(draft CIE Publication 115 [CIE, 12].
Parameter Options Weighting Factor
Speed
Low
Very low (walking speed)
1
0
Very high 1
High 0.5
Traffic volume Moderate 0
Low -0.5
Very low -1
Pedestrians, cyclists and motorized traffic 1
Pedestrians and motorized traffic 0.5
Traffic composition Pedestrians and cyclists only 0.5
Pedestrians only 0
Cyclists only 0
Parked vehicles
Present
Not present
0.5
0
Very high 1
High 0.5
Ambient luminance Moderate 0
Low -0.5
Very low -1
On the basis of data of the total road
lighting park in all European cities we come
to the conclusion that general application of
this system in all European cities would
save some 14 TWh/year. This is the
equivalent of 7 medium electricity power
stations (each of 2 TWhr/year). If in this
table also the earlier-mentioned advantage
of white light would be built in as a
weighing factor, the saving still further
increases.
10 Ingineria Iluminatului 2009; 11, 1: 5-12