Light-Pollution Parameters - Road Lighting: Fundamentals, Technology and Application - page 243

Fig. 16.9 Vertical
illuminance on facades of
neighbouring property

E vert property

Fig. 16.10 Luminous
intensity in the direction of
neighbouring property

I property

16.3.1.2 Luminous Intensity

Residents may be further disturbed by bright lights shining directly into their eyes at
their property. This disturbance can be minimised by limiting the luminous intensity
of luminaires in directions where views of bright parts of the luminaires are likely to
be troublesome for residents in or around their property. Consequently, the limiting
parameter here—again directly related to light arriving at the area of disturbance—is
(Fig. 16.10 ):

I property

Only viewing directions that are likely to be maintained for a longer time should be
taken into account. Momentary and short-time viewing directions should be disre-
garded. With this parameter, compliance can also be checked at the property where
possible disturbance occurs.

16.3.1.3 Facade Luminance

Over-lit bright facades of buildings can be disturbing to both residents and traffic.
It is evident that the limiting lighting parameter here is the luminance of the façade
itself (Fig. 16.11 ):

L facade

Dynamically-changing light levels and colours, as employed in more and more dec-
orative outdoor lighting installations using LEDs, may increase the disturbance to
motorists, cyclists, pedestrians and residents. Flashing lights, as sometimes used
in advertising signs, further increase the disturbance. Research is being conducted