A.3.3 Residential roads

Direct glare from luminaires in subsidiary roads and associated areas, footpaths and cycle ways tracks could be controlled. Where luminaires have clear bowls or refractors, these could conform to class G*1 or a higher installed luminous intensity class to provide adequate control of glare.

A.3.4 Conflict areas

Conflict areas increase the visual demands on the driver, therefore glare in such areas could, as a minimum, be as well controlled as on the approach roads.

Where the luminance design approach of the main through-route can be applied to simple conflict areas, the threshold increment (TI) of the lighting is determined by the selected lighting class. For glare control, it is normally sufficient to use the same luminaires within the conflict area, but if different luminaires are to be used, an appropriate installed luminous intensity class G*l, G*2, G*3, G*4, G*5 or G*6 could be selected.

Where luminance design is not appropriate, and an illuminance class has been selected from Table 2, it is likely that there will be multiple viewing directions of luminaires at varying angles of azimuth, and thus Tl cannot be calculated. In order to limit glare, an appropriate installed luminous intensity class G*l, G*2, G*3, G*4, G*5 or G*6 could be selected.

NOTE Classes G*4, G*5 or G*6 are normally appropriate.

A.4 Obtrusive light

Obtrusive light is light that has undesirable visual effects on the night scenery for residents locally or over large areas.

NOTE Additional information can be found in CIE 126:1997: Guidelines for minimizing sky glow and CIE 150:2003: Guide on the limitation of the effects of obtrusive light from outdoor lighting installations.

All forms of exterior lighting may be sources of obtrusive light. These include road lighting, flood lighting (buildings, monuments, bridges, etc.), illumination of road signs (exterior illumination or transillumination), road signals, lamps on vehicles (headlamps and signal lamps), advertising (illuminated or luminous signs), etc. Even interior lighting may be a source of obtrusive light by light escaping from buildings.

Undesirable effects include:

  1. intrusion of light into rooms, gardens or other property;

  2. domination of the night scenery by luminaires, luminous signs, light signals, illuminated facades and surfaces, etc.;

  3. sky glow.

These effects are considered for road lighting in the following.

Intrusion of light is sometimes considered as a benefit by some residents, for instance when an entrance or a driveway is well illuminated. However, it is generally beneficial to reduce intrusion of light. Methods of reducing intrusive light include the use of luminaires with little spill of light, for instance by selecting luminaires of an appropriate installed luminous intensity class G*l, G*2, G*3, G*4, G*5 or G*6, and to avoid that luminaires are mounted higher than buildings and vegetation along the road.

Domination of the night scenery by road lighting installations can also be avoided by installing luminaires of an appropriate installed luminous intensity class. The luminaires in a road lighting installation in an open area, may be visible over long distances unless they are of a high installed luminous intensity class. Additionally, the utilisation of light, and light falling outside of areas to be illuminated can be considered.

Sky glow is caused by light that is emitted or reflected in an upwards direction towards the sky and then partly reflected back.

The proportion of light that is reflected back is high, when the sky is clouded. In city areas this may cause a significant apparent luminance of the sky and a significant background level of illumination at the ground.

However, sky glow refers mainly to the situation when the sky is clear. The proportion of light that is reflected back is low, depending on atmospheric conditions such as humidity or pollution (smog), but nevertheless high enough to cause an artificial luminance of the sky that reduces visibility of celestial bodies.

One means of reducing sky glow is to use luminaires with little or no emission of upwards light, such as of those with a high installed luminous intensity class G*4, G*5 or G*6. This does not entirely prevent a contribution to sky glow as a proportion of the light emitted from the luminaire is reflected from the road area and its surroundings.

Reduction of light levels in periods of the night may be considered as a mean of energy saving, but has the additional effect of reducing obtrusive light during those periods.

When considering the provision of road lighting, the effects of intrusive light on surroundings should be considered in particular for roads in rural areas as road lighting can rarely be avoided on roads in urban areas

.Annex В


Lighting of pedestrian crossings

Pedestrian crossings may require special consideration. In some countries national standards exist which give further guidance relative to national practices.

When a sufficiently high road surface luminance level can be provided, it may be possible to position the normal road lighting luminaires so as to provide good negative contrast with the pedestrian visible as a dark silhouette against a bright background.

Where local lighting provided by additional luminaires is considered for the illumination of pedestrian crossings the intention should be to directly illuminate pedestrians on or at the crossing and to draw the attention of drivers of motorized vehicles to the presence of the crossing.

The type of the additional luminaires and their positions and orientations relative to the crossing area should be considered so as to achieve positive contrast, and not cause undue glare to drivers. One solution is to mount luminaires a short distance before the crossing in the direction of approaching motorized traffic, and direct the light onto the side of pedestrians facing the drivers of this traffic. For a two way road, a luminaire is mounted before the crossing in each direction of the traffic flow on the side of the road on which traffic drives. Luminaires with asymmetric light output are suitable, causing less glare to drivers.

Local lighting can be arranged to provide sufficient illumination of the pedestrian on the side facing the traffic at all locations of the road crossing area. The illuminance, when measured on a vertical plane, should be significantly higher than the horizontal illuminance produced by road lighting on the carriageway of the road. Zones at either end of the road crossing, where pedestrians wait to enter the crossing, should receive adequate illumination. Lighting confined to a narrow band around the crossing area produces a dramatic affect assisting in raising attention.Annex С

Evaluation of disability glare for C and P classes

For lighting installations of the C and P Classes, limitation of disability glare can be demonstrated by evaluating/ті values in accordance with the methods of EN 13201-3 for all relevant combinations of observation directions and observer positions.

These /л values should not exceed the maximum /ті values specified for the different C classes in Table C.l and P classes in Table C.2.

Table C.l — Maximum /ті values for C classes


/ті [maximum]














Table C.2 — Maximum values for P classes


/ті [maximum]















performance not determined


  1. CEN/TR 13201-1, Road lighting - Part 1: Guidelines on selection of lighting classes

  2. IEC 60050-845, International Electrotechnical Vocabulary (1EV) - Chapter 845: Lighting

  3. EN 12665:2011, Light and lighting - Basic terms and criteria for specifying lighting requirements

  4. CIE Publication 115: 2010, Lighting of roads for motor and pedestrian traffic

  5. CIE Publication 126:1997, Guidelines for minimizing sky glow

  6. CIE Publication 150:2003, Guide on the limitation of the effects of obtrusive light from outdoor

lighting installations