Recently a lighting client contacted our company. Here’s the thing. He took over a road lighting project in his hometown and needed to purchase street lights, so he needed our recommendation.
For such a big topic, there are no drawings, no data, and no requirements. How can ADNLITE recommend it? Road lighting has become more and more popular in the past two years. Below ADNLITE will sort out some relevant standards of road lighting for your reference.
Classification of Road Lighting
First, let’s look at the classification and standards of roads. According to the status of roads in the road network, traffic functions, and service functions for buildings and urban residents along the roads, urban roads are divided into expressways, trunk roads, secondary trunk roads, branch roads, and residential roads.
According to road use function:
- Motor vehicle road lighting
- Non-motor vehicle and pedestrian road lighting
Roads for motor vehicle traffic are divided into three classes:
- Trunk road, expressway
- Secondary trunk road
- Luzhi
Road lighting Evaluation Index
Evaluation indicators for motor vehicle traffic road lighting:
- The average brightness (or illuminance) of the road surface
- Uniformity of road surface brightness
- Glare limitation
- Environmental ratio
- Inductive
Pedestrian road lighting evaluation indicators:
- The average illuminance of the road surface
- Minimum illuminance and vertical illuminance on the road surface
The Standard Value of Road Lighting For Motor Vehicle Traffic Stipulated By The State
The following is the standard value of motor vehicle traffic road lighting in China, where we are located. Each country may have slightly different standards.
Note: This is an asphalt road. If it is a cement concrete pavement, the average illuminance value can be reduced by about 30% accordingly
You can see that there are two indicators of “average brightness” and “average illuminance” in the table. Many people don’t quite understand this.
Illuminance: That is, the luminous flux irradiated on a unit area. It refers to how much light I’m getting somewhere. Its unit of measurement is lux.
Brightness: The human eye observes the light source from one direction, and the ratio of the light intensity in this direction to the area of the light source “seen” by the human eye is defined as the brightness of the light source unit. That is, the luminous intensity per unit projected area. Simply put, it means “how bright it looks in here”. Its unit of measurement is candela per square meter (cd/㎡).
Brightness is the essence of the data we need, but brightness is not easy to test. Therefore, we generally use illuminance to measure.
Overall uniformity: refers to the ratio of the minimum value to the average value on the road surface.
Longitudinal uniformity: refers to the ratio of the minimum value to the maximum value on the center line of the same lane.
Environmental ratio: the ratio of the average horizontal illuminance in the 5m wide area outside the roadway to the average horizontal illuminance on the adjacent 5m wide roadway.
Standard Value of Sidewalk Lighting
How to Choose The Right Street Light
First of all, fast roads and main roads must use cut-off or half-cut light fixtures. Secondly, semi-cut light lamps should be used for secondary trunk roads and branch roads.
Cut-off type luminaire: the angle between the direction of the maximum light intensity of the luminaire and the downward vertical axis of the luminaire is between 0°~65°. Luminaires with a maximum permissible light intensity of 10cd/1000lm and 30cd/1000lm at 90° and 80° respectively. Regardless of the luminous flux of the light source, the maximum luminous intensity in the direction of the 90° angle shall not exceed 1000cd.
Half cut-off type luminaire: The angle between the direction of the maximum light intensity of the luminaire and the downward vertical axis of the luminaire is between 0°~75°. Luminaires with a maximum permissible light intensity of 50cd/1000lm and 100cd/1000lm at 90° and 80° respectively. Regardless of the luminous flux of the light source, its maximum luminous intensity in the direction of the 90° angle shall not exceed 1000cd.
Arrangement of Lamps
First of all, fast roads and main roads must use cut-off or half-cut light fixtures. Secondly, semi-cut light lamps should be used for secondary trunk roads and branch roads.
Cut-off type luminaire: the angle between the direction of the maximum light intensity of the luminaire and the downward vertical axis of the luminaire is between 0°~65°. Luminaires with a maximum permissible light intensity of 10cd/1000lm and 30cd/1000lm at 90° and 80° respectively. Regardless of the luminous flux of the light source, the maximum luminous intensity in the direction of the 90° angle shall not exceed 1000cd.
Half cut-off type luminaire: The angle between the direction of the maximum light intensity of the luminaire and the downward vertical axis of the luminaire is between 0°~75°. Luminaires with a maximum permissible light intensity of 50cd/1000lm and 100cd/1000lm at 90° and 80° respectively. Regardless of the luminous flux of the light source, its maximum luminous intensity in the direction of the 90° angle shall not exceed 1000cd.
(a) Unilateral arrangement (b) Bilateral staggered arrangement (c) Bilateral symmetrical arrangement (d) Central symmetrical arrangement
So in street lamps, what is the relationship between the light distribution type and arrangement of lamps and the installation height and spacing of lamps? Please see the table below.
Cut-off type: The height of the light poles arranged on one side must be higher than the effective width of the road, and the spacing should be less than 3 times the height of the light poles. For example, for a light pole with a height of 8m, the distance between lights should not exceed 24m.
Installation height: the vertical distance from the light center of the lamp to the road surface.
Overhang length: the horizontal distance from the light center of the luminaire to the edge stone on the adjacent side. That is, the horizontal distance that the lamp protrudes or retracts from the edge stone. Generally, it should not exceed 1/4 of the installation height, and the elevation angle of the lamp should not exceed 15°.
Weff: Effective width of road surface
The choice of lighting arrangement is particularly important for road lighting, because it is inductive, and a good lighting arrangement can reduce the occurrence of road accidents.
Inductiveness: Appropriate installation of light poles and lamps along the road can provide drivers with visual information about the direction, line shape, and slope of the road ahead.
