The solar highway lighting system has many different applications, and one of them is to light up highways. Long distance road users need to travel with excellent visibility when it gets dark. They also need to drive in comfort and safety, knowing that all road signs and markings are visible to them. For the fundamentals of how these systems work, our guide on the solar street light working principle is a helpful companion read.
A well designed, energy efficient solar highway lighting system should help local authorities reduce energy use and costs. The energy produced can be used to enhance the appearance of the settlements along the highway.
The use of a solar highway lighting system to illuminate highways can cut the cost of installation. It is possible to reduce the cost of installing standard grid systems by 50 percent with solar technology. Energy efficient technology is required where the energy from the mains is not enough to power an entire or part of the highway.
However, highways cut across different regions of varying characteristics. The amount of efficiency along the road will not be the same, as some places experience more sunlight than others. Safety can be a factor of consideration too. The above challenges could be the reason why most developing countries place these lighting systems in towns along the highways.
There are lighting standards for the solar highway lighting system. Here is some vital information that you can use in your upcoming project.
Lighting Requirements
When designing a solar highway lighting system, it is essential first to understand the light requirements of the road distance based on the traffic density of the road. This information will help you determine the installation specifications for your system. You can obtain this information from the existing Code of Practice for the lighting of public roads. Our guide on how to calculate the distance for LED solar area lights helps with spacing and coverage.
Matching Intensity with Traffic Trends
In most solar highway lighting systems, the intensity of the light source changes depending on the traffic on the road. You can quickly achieve this type of automation by using timers or motion sensor technology in the dimming systems.
By using a timer, the solar highway lighting system can adjust its illumination as time goes on. The use of the timer method to control the levels of light is supported by research to determine the traffic behavior of the area that needs visibility.
The use of motion sensor technology relies on the level of activity below the unit to increase or decrease the intensity of light. When a car approaches, the solar unit will produce more light to make the road clear. The auto intensity control requires the use of a Pulse Width Modulation (PWM) technique and a programmable microcontroller to work. Learn more in our post on the 8 benefits of a solar sensor street light and our guide to the solar street light controller.
Selection of Light Source
Most modern solar highway lighting systems use light emitting diode (LED) and Compact Fluorescent Light (CFL) to light up the highway at night. These two types of lamps are known for producing brighter light that increases the visibility of external objects, which would stay in the shadows when traditional or conventional lights are used.
It is a requirement that one should use a lighting fixture that has low energy consumption or high energy savings, low maintenance, no mercury, and a long lifespan. Also, the selected lamp should have excellent color rendering properties and maintain illumination for an extended period. The luminous efficacy, or the measure of lumens per watt, also plays a vital role in this section. Our comparison of HPS lights vs LEDs in outdoor solar street lamps explores light source selection in depth.
Selection of Luminaire
The luminaire, as a complete unit, consists of the light source, power supplies, control mechanisms, optical elements (the reflector and refractor), the fixture, the housing, and other electronics. These are the components and parts that help support and position the bulb, connect the lamp to the power supply, and distribute the light. To understand these parts better, see our post on the anatomy of solar LED street light luminaires.
The optical elements are essential in controlling glare and light pollution. Luminaires can be categorized based on the cutoff optical system (which aims to reduce the degree of glare). The available types include full cutoff, cutoff, semi cutoff, and non cutoff luminaires.
Therefore, it is critical to comply with the glare requirement, limiting the intensity of light in the region where you wish to install the luminaire. In some areas, the glare zone is limited to between 80° and 90°.
Type of Switch
Auto switching is a cost effective method for turning the solar highway lighting system on and off without any human intervention. You can achieve this technique by using light detector devices such as LDRs (light dependent resistors), photoresistors, photodiodes, and PIR (passive infrared) detectors in the control mechanisms.
Pole Type, Height, and Spacing
The standards for a solar highway lighting system also specify the material used for the pole, the dimensional size, and the distribution pattern. The type of pole material you use should factor in the weight, resistance to wind, and lifespan of the pole. Our 9 factors for choosing solar power light poles can guide this decision.
Adhering to the standard pole spacing pattern and the recommended mounting height of the luminaires should provide the required light for the highway.
The lighting standard for a solar highway lighting system requires:
- Proper pole height and spacing meet uniform light distribution and levels for safety and security needs.
- Proper luminaire aesthetics blends well with the surrounding environment.
- High lamp efficacy and luminaire efficiency minimizes energy consumption and cost, and prolongs the lifespan of the light source.
- High lumen maintenance reduces the replacement cost of the luminaires.
- Excellent color rendering improves visibility and security by providing close to natural lighting properties.
- The proper cutoff provides adequate optical control and minimizes light glare and pollution.
- Automatic switching reduces energy wastage and lowers maintenance costs.
Solar Highway Lighting System: Conclusion
The lighting standards for the solar highway lighting system aim to meet the local lighting requirements while at the same time achieving maximum energy efficiency. The system must be appropriate for the site and should provide the level of illumination and uniformity of light specified by the street light codes of the region. For a broader buying checklist, see our list of the 10 things about the best solar street lights.
Some standards may vary from one country to another, but international bodies control most of them. Abiding by the rules of lighting is the way to go to ensure safety and the conservation of nature using green technology. The U.S. Department of Energy offers further guidance on efficient LED roadway lighting.
Frequently Asked Questions (FAQs)
1. What is a solar highway lighting system?
A solar highway lighting system is an off grid or hybrid lighting solution that uses solar panels, batteries, and LED luminaires to illuminate highways, roads, and settlements along them. It provides safe nighttime visibility while cutting installation and energy costs compared to traditional grid powered systems.
2. How much can a solar highway lighting system save on installation?
A solar highway lighting system can reduce the cost of installing standard grid systems by up to 50 percent. Because it needs no trenching, cabling, or mains connection, it is especially cost effective for long stretches of highway and remote areas.
3. How does a solar highway lighting system adjust brightness for traffic?
A solar highway lighting system adjusts brightness using timers or motion sensors. Timers dim the lights based on researched traffic patterns, while motion sensors brighten the light when a vehicle approaches and dim it when the road is empty, using PWM control and a programmable microcontroller.
4. What type of luminaire is best for a solar highway lighting system?
The best luminaire for a solar highway lighting system uses efficient LEDs with high lumens per watt, excellent color rendering, long lifespan, and a proper cutoff optical system (full cutoff or cutoff) to control glare and light pollution while ensuring uniform road illumination.
5. What standards must a solar highway lighting system meet?
A solar highway lighting system must meet standards for proper pole height and spacing, uniform light distribution, high lamp efficacy and luminaire efficiency, high lumen maintenance, excellent color rendering, proper glare cutoff, and automatic switching. These vary by country but are largely governed by international bodies.