There are more than 300 million street lighting fixtures installed worldwide, most of which are still of traditional technology (vapor mercury, sodium and metal halide). However, lighting stocks are changing dramatically due to the technical and economic advantages offered by LED technology.
These changes are mainly due to the reduction of consumption and the improvement of the energy efficiency of the installation. However, it must always be kept in mind that good street lighting is designed to provide good visibility for the safety of residents and road users.
The key to achieving correct visibility on the street is the light distribution obtained through the correct selection of the luminaire’s secondary optics. The purpose of these optics is to direct the light generated by the LEDs where it is needed on the road, avoiding those areas where it does not need to be illuminated (sky, buildings…). This results in a good level of uniformity as it improves the control of the beam towards the desired point, has low glare, reduces light pollution and leads to significant energy savings.
The variety of existing road types and the standards applicable to each leads to the need for optics with many different photometric distributions to respond to any outdoor application. In this regard, it needs to be emphasized that the optics in LED lighting play a crucial role in the overall success of the lighting fixture. This is because the luminaire itself is responsible for controlling and distributing the light emitted by the lighting system.
From a wide range of optics and light distributions, we will examine three main examples: M1 street lighting for roads; P1 street lighting for sidewalks; and finally, street lighting for pedestrian crossings.
M1 street lighting for roads:
Class M1 street lighting is the most demanding of all M classes. As reflected in the EN13201 standard, on roads, urban and residential roads, at medium to high speeds.
Special optics had to be used to solve lighting problems for class M roads. As part of its photometric portfolio for road lighting luminaires, ELT supplies ME, which fulfills all the requirements shown in the following light study.
P1 sidewalk street lighting:
The latest update to the EN13201 standard includes Class P street lighting for pedestrians and cyclists on sidewalks, cycle paths, escape routes and other roadways.
When analyzing pavements classified as P1, the SCL light distribution is the best choice for all requirements.
Street lighting for pedestrian crossings:
According to a study by the Mapfre Foundation, 40% of collisions occur on pedestrian crossings, so it is important to light them correctly to achieve the maximum level of safety for residents and road users.
In street lighting for pedestrian crossings, the minimum reference illuminance in the vertical axis is 40 lux with a glare limit of G2 in the direction of traffic flow and a limit of G3 glare in the direction of pedestrians.
To meet these demanding requirements, ELT selected two suitable optics: PX, which highlights the crosswalk for traffic coming from the right; and PXL, which highlights the crosswalk for traffic coming from the left.
This is a simple study of the crosswalk for traffic coming from the right.