The installation distance of street lights mainly depends on the following factors:

1. Road width
   • Generally speaking, the wider the road, the larger the installation distance of street lights can be.
   • For example, for major urban arterial roads wider than 20 meters, the spacing between street lights can be appropriately increased.
   • In comparison, for secondary urban roads and rural roads with smaller widths, the spacing of street lights should be relatively shorter.
2. Lighting requirements
   • Different grade roads and usage scenarios have different lighting requirements.
   • Major roads require higher illuminance and uniformity, so the installation distance should be reduced.
   • For secondary roads and pedestrian paths with relatively lower lighting requirements, the installation distance can be appropriately increased.
3. Luminaire power and beam angle
   • Street lights with higher power and narrower beam angles can be installed at greater distances.
   • For low-power street lights with wide beam angles, the installation distance should be reduced.
4. Building height
   • If street lights are installed in areas with taller buildings, the installation distance can be increased.
   • In areas with lower buildings, the installation distance should be shortened.
5. Environmental factors
   • Surrounding environments such as trees and buildings can affect the lighting effect, and the spacing of street lights should be adjusted accordingly.
   • Adverse weather conditions like hazy weather can also reduce the lighting effect, in which case the spacing of street lights should be reduced.

In general, the installation distance of street lights needs to be comprehensively considered based on the specific road conditions, lighting requirements, luminaire performance, and environmental factors to ensure good lighting effects. Typically, the spacing of street lights on major urban arterial roads is 30-50 meters, and 20-30 meters is better for secondary urban roads and rural roads.