The number of street lamps in the world has exceeded 300 million and is still increasing. Although LED Street Lights have obvious technical and economic advantages, most street lamps have not yet been converted into LED lamps. Although the official requirements vary from region to region, the main principles of good LED Street Lighting are the same: high-quality lighting, ensuring clear visibility and road safety. Whether it is a small sidewalk, a multi-lane highway, a crosswalk or a tunnel, there are many ways to achieve reasonable lighting.

Then the Optics System plays a very important role.

Luminous efficiency (lm/w)- get what you need with the lowest loss

Brightness (cd/m2) or brightness level (lx)- brightness and lighting level on the road

Uniformity Uo- Good lighting uniformity on the road to ensure road safety and clear visibility of all areas.

Glare T1- Excessive or irritating light will reduce the vision of pedestrians, drivers and others on the road, which is usually caused by excessive light distribution.

Light pollution- Upward lighting causes unnecessary sky glow in urban areas. Unnecessary backlight and overflow light can illuminate neighboring residential areas and even disrupt people's sleep.

Flexibility- Through good design, the number of light distribution variants that can be provided according to different street lighting arrangements and requirements.

LED Street Lighting Light Distribution

The light distribution of LED Street Lamps will vary according to the geometry of the road, the type of road, and the location and direction of the lamps. Road geometry is the main factor that affects the beam pattern of lighting equipment. Road lighting equipment can be classified according to lateral and lateral light distribution.

The lateral light distribution is divided into three groups:

Short (S): The lateral distance is from 1.0 to less than 2.25 times the installation height.

Medium (M): The lateral distance is from 2.25 to less than 3.75 times the installation height.

Long (L): The lateral distance is from 3.75 to less than 6.0 times the installation height.

Lateral light distribution includes:

Type I (applicable to a 1-lane or 2-lane roadway, the width of the roadway is approximately equal to the installation height)

Type II (intended to accommodate a 4-lane carriageway or a carriageway whose width is less than 1.75 times the installation height)

Type III (applicable for roads or areas with a width of 1.75-2.75 times the installation height)

Type IV (used for roads or areas whose width exceeds 2.75 times the installation height)

Type V (circular symmetry of candlelight distribution)

Type VS (square symmetry of candle power distribution)

Luminaire Classification System (LCS)

The effect of outdoor lighting systems on the environment are under increasing scrutiny. The presence of bright sources in the periphery of the field of view may compromise road visibility and cause feelings of discomfort. As such, precise cutoff of light is required in outdoor applications to eliminate urban sky glow (light pollution), light trespass, and glare. This system evaluates fixtures for the amount of light emanating in all directions to include potential nuisance lighting, including backlight, uplight, and forward light. LCS describes the amount of light in each of these three primary angles to classify each fixture by the BUG rating.

Backlight: Backlight describes the lumen distribution away from the street (house side). A B0 rating requires less than 110 or 220 lumens directed behind the luminaire/pole depending on the angle. A B0 or B1 rating may require a shield or optic limiter to block light emanating towards private property for typical street light fixtures. Typical rating for a LED luminaire equivalent to a 250 watt HPS fixture would be B3.

Uplight: Uplight describes the lumen distribution emanating above the horizontal plane at a luminaire. U0 rating requires zero lumens directed above the luminaire. Most typical LED street luminaires achieve this U0 rating independent of the number of total lumens from the luminaire. Decorative fixtures could emit lumens above horizontal and have a U rating higher than zero.

Glare: Glare describes the lumen distribution emanating at a high angle below the horizontal plane of the luminaire. This is the visual light that will cause discomfort to drivers. Typical rating for a LED luminaire equivalent to a 250 watt HPS fixture would be G3. Use caution when specifying the use of dark-sky or night-sky compliant LED luminaires.

The International Dark-Sky Association (IDA) has recommendations and has approved luminaires as dark-sky friendly. Those luminaires do include no uplight (U0), but also include an orange tone (similar to HPS, 3,000 degree Kelvin) to minimize reflected blue light from pavement surface.

The world is full of different roads and strict street lighting requirements. That is why Xindeco LED Street Lights offer so many specific light distributions for all road lighting to help you meet these requirements. Xindeco full range of  advantaged LED Street Lighting certified by CB, IECEE, SASO 2927, ENEC, CE, Inmetro can meet any public lighting project demand, please Contact Us for any enquiry.