Road lighting should be designed to reduce visual discomfort

Roadway and Street Lighting

Regardless of what type of lighting system you are using, road lighting should be designed to reduce visual discomfort. Whether it is the absence of road lights or the presence of high luminance street lighting, you should pay attention to the size and color of each light source. This information is essential for object identification and estimating how far away the object is from the viewer. CIE's Road classification system classes 12 different types of roads into five different zones: highway, rural, industrial, and traffic conflict areas.

The primary goal of roadway and street lighting is visibility and safety. Lighting in the United States generally uses high-intensity discharge (HID) light sources, metal halide, and high pressure sodium lamps. HPS lamps produce the highest lumens, but have a yellowish tint, while metal halide bulbs have a white appearance. However, luminosity alone doesn't tell the story of visibility. Consider all these factors when selecting a lighting system for your roadway.

Choosing the right lighting system is essential for safety. Depending on the nature of the roadway, it may be necessary to make adjustments to the lighting system. Some lighting systems are designed to prevent light trespass. However, other lighting systems may serve other purposes as well, such as improving peripheral vision and detecting large animals. However, it can be difficult to balance the needs of road users with their effects. This is why road lighting must be planned holistically.

In addition to the aesthetic value of lighting, road illumination also reduces the risk of collisions. CIE estimates that road lighting can reduce personal injury RTC by 30%, depending on the type of lighting used. Roadlights can also reduce the cost of road maintenance. In 2005, road lighting was responsible for 8% of all lighting electricity. In addition, roadlighting uses a significant amount of energy. It consumed 218 TWh of electricity.

The Illuminance of street lights is measured using the Iso-Lux diagram. The highest Illuminance point is called the "Nadir Point." All other points are given an Illuminance level that is proportional to the Emax of the Nadir Point. If they are 73% of the Emax of the Nadir Point, then the Iso-Lux diagram will look like the following. It is important to follow the rules of Iso-Lux measurements for safe road lighting.

The spectral sensitivity of roadlights affects the driver's perception of objects. There are two types of contrast: color and photometric. Both affect how well drivers can perceive a hazard. The brightness of the road, the glare of approaching vehicles, and the amount of time it takes to notice a hazard are all factors that influence driver adaptation. Understanding these effects is critical to designing effective roadway lighting systems.

In addition to improving safety, road lighting also provides personal security benefits. People who drive in the dark lose the sense of personal security. Deep shadows reduce personal security and comfort. Research conducted by Elvik and Vaa (2004) shows that lighting reduces crashes by between 20 and 30 percent. It also reduces the number of fatalities and injury crashes. It also decreases nighttime crashes by up to 50 percent. This reduction can be seen in rural areas and freeways, as well.