Road lighting rules
Road lighting is essential to ensure safety and visibility for drivers, cyclists and pedestrians. To achieve optimal lighting conditions, it is important to follow established rules and standards. In Europe, the European Committee for Standardization (CEN) has developed standards under the EN (European Norm) framework that provide guidelines for road lighting design. Understanding these standards is crucial to designing effective road lighting systems.
The primary EN standard that regulates road lighting design is EN 13201. This standard specifies the requirements for road lighting design, including parameters such as luminance, illuminance, uniformity and glare control. It categorizes roads into different classes based on their function, traffic volume and speed and provides specific lighting criteria for each category. In general, roads can be divided into the following basic components:
Roads: Highways require uniform lighting with sufficient brightness to ensure visibility at high speeds. Lighting fixtures are typically mounted on poles along the roadside and provide uniform illumination across the entire road.
Cycle paths: Cycle paths may require lower lighting levels compared to main roads, but still need sufficient lighting for cyclist safety. Lighting fixtures are often mounted at a lower height than lamps for road lighting.
Sidewalk: Sidewalks require uniform lighting to ensure pedestrian safety and comfort. Lighting fixtures can be installed at lower heights or integrated into architectural elements to provide sufficient light without causing discomfort.
Intersections: Intersections require improved lighting to improve visibility and reduce the risk of accidents. Intersection lighting should focus on illuminating pedestrian crossings and directional signs effectively.
Tunnel lighting: Lighting specifically designed for tunnels to ensure visibility and safety for drivers changing from daylight to low light.
Glare Rating (GR) is one of the important indicators in road lighting. It measures the uncomfortable glare produced by a lighting installation. High levels of glare can reduce visibility and cause discomfort for drivers, potentially leading to safety risks. EN 13201 provides guidelines to limit glare and recommends specific maximum GR values for different road categories. For example, this standard sets stricter limits for glare on main roads with high traffic volumes and speeds compared to residential roads. Correlated color temperature (CCT) plays a crucial role in road lighting and affects visibility, comfort and safety. While there is no one size fits all CCT for roadway lighting, a common recommendation is to use cooler color temperatures (5000-6000K) for roads. Here's why:
Visibility: Cooler CCTs tend to improve visibility, especially in low light or bad weather. This improves contrast, making it easier for drivers to distinguish objects on the road.
Color recognition: Cooler temperatures provide better color recognition in traffic, ensuring that directional signs, markings and signal lights are accurately perceived by drivers. Thus, it cannot always be equated that a warm color temperature of 3000K has better color rendering in traffic than say 5000K, even if the color rendering index (CRI) is higher.
Psychological impact: Higher CCTs can create a perception of increased safety and alertness among road users, contributing to a sense of safety during night driving. The cooler light is registered by humans as daylight and provides more energy.
However, it's important to balance the benefits of cooler CCTs with considerations such as light pollution and the potential impact on wildlife. For example, Copenhagen in Denmark has implemented LED street lighting with a CCT of 3000K and 4000K, maintaining a balance between visibility and environmental concerns. The lighting system provides sufficient illumination for road users while minimizing damage to the environment.
Wet roads are one of the main challenges for drivers. Rainwater creates reflective surfaces, causing glare from oncoming headlights and reducing visibility. In addition, the water film on the road can blur lane markings and other essential signs for drivers. Denmark is known for having the strictest guidelines and legislation on wet roads. Here are two of the most effective solutions to improve visibility in bad weather conditions:
Increase lighting levels on wet roads to compensate for reduced visibility caused by rain, fog or haze by implementing dynamic lighting control systems. These systems adjust lighting levels based on real-time weather conditions, traffic flow and road accidents.
Use properly selected lamp optics to minimize glare from wet surfaces and focus light on road markings and signage.
In conclusion, adhering to EN standards, selecting appropriate CCTs and optical beam angles, and understanding the unique lighting needs of different road elements are essential aspects of road lighting design. By following these guidelines, designers can create lighting installations that prioritize safety, visibility, and comfort for all road users without causing major damage to the environment. In the learning environment, an article on Dark Sky regulations will be available later this year. This article is very relevant for pathway systems, street lighting and other areas where light pollution may be present. Remember to sign up for our newsletter and the new posts will be at your fingertips.