What are the lighting requirements for different types of rural roads?
There are various types of rural roads (such as field paths, village-level main roads, township connecting lines, special dangerous sections, etc.). The core of the "lighting requirements" for lighting fixtures is: let the light cover the road surface accurately, avoid "distorted", "scattered", "uneven brightness", and reduce light pollution to the surrounding environment (such as not directly shining on farmland and houses). The differences in lighting requirements for different types of roads are mainly reflected in the three core dimensions of "light distribution range", "uniformity", and "glare control", as follows:
1. Narrow roads/branch roads (such as field paths, sidewalks between houses): require "centralized lighting to avoid waste"
Road characteristics
Width 1.5-3 meters, no motor vehicles, only pedestrians and bicycles; the surrounding area is mostly farmland and houses, and light should be avoided from directly shining on houses or farmland (to avoid affecting rest and crop growth).
Core requirements for light distribution
Light distribution type: narrow light distribution (beam angle 60°-90°)
The light is concentrated within the road surface (covering 1.5-3 meters horizontally and 10-15 meters vertically), and does not spread to the sides (avoiding illuminating non-road areas).
Example: The light distribution curve of the lamp is "narrow and long", and the light is mainly projected to the road directly below and in front, and the light intensity on both sides (0.5 meters outside the curb) decays rapidly.
Uniformity: Basic uniformity is sufficient (minimum illumination / average illumination ≥ 0.3)
No need for strict uniformity (after all, only pedestrians pass), but avoid "single point too bright, surrounding dark" (such as too bright directly below the lamp, can not be seen a few steps away), to prevent visual adaptation difficulties.
Glare control: low glare (UGR≤25)
The pedestrian sightline is close to the height of the lamp (the installation height of the small road lamp is mostly 3-5 meters), and the lamp should be prevented from directly shining into the human eye (such as choosing a lamp with a sunshade, or the lamp elevation angle is ≤15°).
2. Village-level main roads/secondary roads (such as the main road in the village and the connecting road of the village group): require "wide-band lighting and uniform coverage"
Road characteristics
Width 3-6 meters, motor vehicles (electric vehicles, agricultural tricycles, small cars) pass at low speed (≤20km/h), and the flow of people is medium; there may be houses and green belts on both sides of the road, and it is necessary to take into account the road lighting and the surrounding environment.
Core requirements for light distribution
Light distribution type: medium light distribution (beam angle 90°-120°)
Horizontally cover the road surface and the range of 0.5-1 meters on both sides (total width 4-7 meters), and vertically cover 15-20 meters (matching the street lamp spacing of 20-25 meters), ensuring that the light of two adjacent lamps is "seamlessly connected" on the road surface (no obvious dark area).
Example: The light distribution curve is "fan-shaped wide", and the light spreads evenly to both sides of the road, but does not exceed 1 meter from the roadside (avoid direct exposure to residential windows).
Uniformity: high uniformity (minimum illumination / average illumination ≥ 0.4)
Motor vehicles need to avoid "alternation between light and dark" (otherwise the driver's vision frequently adapts and is prone to fatigue), and the road illumination fluctuation is required to be small (such as average illumination 8-12lux, minimum illumination not less than 3.2lux).
Glare control: medium glare (UGR≤22)
The sight line of the motor vehicle driver may be flush with the height of the lamp (the installation height of the street lamp is 5-6 meters), and the "upward light" of the lamp needs to be controlled (to avoid the light directly shining into the eyes of the oncoming driver when meeting at night). "Half-light type lamp" (upward light ratio ≤10%) can be selected.
3. Township connecting line/key road section (such as roads connecting townships and villages, main roads at the entrance of villages): "wide width + directional lighting, taking into account safe sight distance" is required
Road characteristics
Width 6-9 meters, increased motor vehicle traffic (speed 20-40km/h), there may be intersections and village distribution points; it is necessary to ensure that the driver "sees the road markings, pedestrians, obstacles clearly", as well as visual safety when meeting.
Core requirements for lighting distribution
Light distribution type: wide lighting distribution + directional lighting distribution (beam angle 120°-150°, with lateral offset)
Lateral coverage of the road surface and both sides is 1-1.5 meters (total width 8-10 meters), and longitudinal coverage is 20-25 meters (matching the street lamp spacing of 25-30 meters);
If there are houses on one side of the road and farmland on the other side, "asymmetric lighting distribution" can be selected (the light is slightly biased toward the farmland side and away from the house side to reduce the impact on residents).
Uniformity: high uniformity (minimum illumination / average illumination ≥ 0.5)
After the speed of motor vehicles increases, the requirements for "continuous lighting" are higher, and it is necessary to avoid "dark spots" on the road surface (such as a sudden drop in illumination between two lights). The average illumination is recommended to be 10-15lux to ensure that the driver can find road obstacles (such as stones and potholes) 5-10 meters in advance.
Glare control: Strict glare (UGR≤20)
Direct light when meeting other vehicles can easily cause "momentary blindness", so "cut-off type lamps" (upward light ratio ≤5%) should be selected, and the lamp installation height should be ≥6 meters (the higher the height, the less likely it is to directly hit the human eye), and the lampshade should be frosted or anti-glare (softening the light).
Special dangerous sections (such as curves, ramps, bridges, intersections): "targeted supplementary lighting to eliminate blind spots" is required
Road characteristics
There are safety hazards (such as obstructed vision on curves, unclear bottom of ramps, and easy conflicts at intersections), and "dangerous areas" should be illuminated first, rather than evenly covered.
Core requirements for light distribution
Curve: directional light distribution (lighting up the inside of the curve)
Conventional street lamps have symmetrical light distribution, and curves are prone to "bright outside and dark inside" (the inside is a blind spot), so "asymmetric directional light distribution" (the light beam is offset 10°-15° to the inside of the curve) is required to ensure that the driver can see the inside road surface and whether there are pedestrians/obstacles.
Ramp: longitudinal extension light distribution (extend the illumination distance)
When going uphill, you need to see the top of the slope clearly in advance, and when going downhill, you need to see the bottom of the slope. The light distribution needs to "cover longer longitudinally" (5-10 meters more than the same width straight road), and "long-distance light distribution" lamps can be selected (the longitudinal beam angle is elongated to reduce the concentration of light in the near distance).
Intersection: Omnidirectional wide light distribution (no blind spot coverage)
The intersection needs to illuminate vehicles and pedestrians from all directions at the same time, and the light distribution needs to be "360° wide coverage" (beam angle of more than 150°), and the central illumination is improved (30% higher than the surrounding road sections) to ensure that all parties can see the whole picture of the intersection.
Summary: The "core principle" of rural road light distribution
"Light distribution on demand" rather than "blindly choose a large beam angle": narrow light distribution is used for narrow roads (energy saving and pollution prevention), and wide light distribution is used for wide roads (to ensure coverage);
Uniformity takes precedence over brightness: the speed of rural roads is not high, and "uniform light and dark" is more important than "absolute brightness" (to avoid visual fatigue);
Adaptive installation conditions: Light distribution needs to be combined with the installation height of the street lamp (if the height is low, the beam angle should be small to avoid light spilling out of the road; if the height is high, the beam angle should be large to avoid light concentrating in a small area).
When making the actual selection, you can ask the lamp manufacturer to provide a "light distribution curve chart" (which visually displays the light distribution range), or conduct on-site tests (after lighting up, observe whether the road surface is evenly illuminated, and whether there are obvious dark areas or light overflow), and then make adjustments based on the actual road conditions.
