Good tunnel lighting is essential to ensure that drivers are able to adapt quickly when entering a tunnel and to ensure that they can drive safely in the tunnel. The driver must enter the tunnel safely, pass through it without incident and exit the tunnel.
Tunnel lighting has its own special requirements due to the contrast between the brightness of the day and the darkness inside the tunnel. Due to the low level of illumination inside the tunnel and the high level of sunlight outside, drivers may experience temporary blindness. In order to prevent potential accidents, the lighting must change gradually so that drivers can adapt.
Tunnel Lighting Design Principles
As tunnels are semi-enclosed structures, tunnel lighting is more complex than conventional lighting and requires adequate lighting to ensure safe driving. Drivers must remain focused and maintain a steady speed when exiting the tunnel, especially during the day when the tunnel has a large brightness contrast with the outside world. Therefore, tunnel lighting design needs to follow several key principles.
1. Partitioned lighting
The most significant feature of tunnel lighting is its zoning function. According to the driver's visual needs, the lighting is usually divided into four areas:
Entrance Zone: The high level of illumination here helps to eliminate the “black hole effect” and enables drivers to quickly adapt to the tunnel lighting.
Transition Zone: The light level in this zone is gradually reduced to help the driver's eyes adjust.
Intermediate Zone: this area of the main tunnel is steadily illuminated, ensuring optimum visibility throughout.
Exit Zone: Lighting is gradually increased to help drivers adjust to the higher level of brightness outside and to eliminate the “white hole effect”.
The lighting system is based on a combination of basic and intensified lighting, with the center section designed for basic lighting and additional high-powered luminaires to enhance visibility. Emergency areas also have specific lighting requirements.
2. Avoiding the effects of smog
Due to insufficient ventilation, vehicle exhaust can cause smoke build-up in tunnels, thus affecting visibility. Lighting design must therefore take into account the potential effects of smoke.
3. Brightness and uniformity
Effective tunnel lighting requires proper average brightness and uniform distribution. Significant differences in brightness can produce glare and strobe effects that can affect visual comfort. Key considerations include:
Overall luminance uniformity: the ratio of the minimum luminance to the average luminance of the tunnel roadway.
Longitudinal uniformity: the ratio of the minimum roadway luminance to the maximum roadway luminance along the lane axis.
It is critical to select LED linear luminaires that provide uniform light without flicker or glare.
4. Glare Control
Glare from high brightness or high contrast can impair vision and cause discomfort. Glare can come from vehicle headlamps, tunnel luminaires, or a bright exterior environment. To mitigate glare, tunnel luminaires should be designed with cut-offs and utilize diffuse reflective technology to soften the entry of light.
5. Avoid strobe effect
Strobe effects can occur in longer tunnels due to uneven lighting arrangements, and constant light changes can cause discomfort. Strobe frequencies should be kept between 2.5 Hz and 16 Hz to ensure acceptable strobe effects, and installation spacing needs to be carefully adjusted to prevent frequencies between 4 Hz and 11 Hz.
6. Lighting Management and Control
Advanced lighting control systems are essential to increase energy efficiency and improve lighting conditions. Intelligent systems equipped with light sensors and dimmable rectifiers can dynamically adjust lighting levels according to the time of day and traffic flow, thereby improving visibility and reducing energy consumption.
What are the lux levels for tunnel lighting?
The lux level of tunnel lighting varies according to the different parts of the tunnel:
Entrance Zone: usually between 500 lux and 1,000 lux. This range helps the driver's eyes to gradually adjust from the bright outdoor environment to the lower light levels inside the tunnel.
Transition Zone: The brightness gradually decreases, ranging from 200 lux to 500 lux.
Intermediate Zone: Brightness remains constant, usually between 50 lux and 200 lux, ensuring that the driver can clearly see the road and any obstacles.
Exit Zone: the brightness gradually increases, ranging from 200 lux to 500 lux, to help drivers readjust to the high brightness of the outdoor environment.
What lights should be used in tunnels?
LED lamps are ideal for tunnel lighting because they offer:
Energy efficiency: high photovoltaic conversion efficiency significantly reduces energy consumption.
Long service life: With a service life of more than 50,000 hours, the need for frequent replacements is minimized.
Intelligent dimming: LEDs can dynamically adjust brightness according to actual demand, enhancing energy efficiency and visual comfort.
High reliability and stability: performs well in a variety of environmental conditions.
Environmental benefits: LEDs are eco-friendly, meet environmental standards and minimize light pollution.
By choosing the right LED lamps, you can ensure that your tunnel lighting system is efficient, reliable and sustainable.
We have extensive experience in tunnel lighting upgrades, whether we provide retrofit kits or complete luminaires.
The key features of our tunnel lights are as follows:
1. A wide range of optical options to meet all tender requirements.
2. Long life span, LEDs have a life span of over 50,000 hours, which reduces replacement frequency and lowers maintenance costs.
3. High efficiency, 160lm/W.
4. Vibration and corrosion resistant.
5. Dali2, D4i, dimming function, can automatically adjust the brightness according to traffic flow, time and weather conditions.
6. Environmental protection: LED does not contain harmful substances, low light pollution.
If you need help with your tunnel light project, please feel free to contact us for solutions.
E-mail: rokee@rokeelighting.net
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