Automobile exhaust, noise, vibration, polluted air, corrosive gases, moisture and other harsh environments formed tunnel lighting particularity. In order to give vehicular traffic and pedestrians with a safe and comfortable lighting environment, the following analyzes to elaborate tunnel lighting design ideas and methods.
Unlike road led tunnel light lighting has its distinct specificity, and its security concerns in the lighting system is particularly important.
In the design of tunnel lighting options, taking into account the human factor in light adaptation and dark adaptation, attention to transition and transition lighting design. To meet the drivers eyes suitability requirements, as required in a dark tunnel entrance transitional lighting to ensure a certain vision requirements. Tunnel exit due to adaptation time is very short, usually less than 1s, it may be used for other processing.
Usually there are several special tunnel vision problems:
(A) before entering the tunnel (daytime): As great differences in brightness within and outside the tunnel, so to see from outside the tunnel, the tunnel entrance very inadequate lighting will see the “black hole” phenomenon.
(2) into the tunnel (daytime): bright outside into the car by a very dark tunnel even after a certain time to go through in order to see the situation inside the tunnel, known as the “adaptation lag” phenomenon.
(3) tunnel exit: During the day, a motor vehicle through a long tunnel near the exit, due to see the outside through the export of high brightness, exports appears to be a “white hole”, there will be a strong glare, driver would feel uncomfortable; night and day on the contrary, see not lit tunnel exit hole but a black hole, so that the driver will not see outside the linear and road obstacles.
Several more special visual problems to tunnel lighting made higher requirements, an effective solution to these visual problems, you can use the following aspects.
A tunnel lighting settings
Tunnel lighting generally divided into sections, to adapt stage, transitional stage, the basic and outlet sections of five lighting, where each section has a different role:
(A) the introduction paragraph: the elimination of “black hole” phenomenon, so that the driver can identify obstructions in the hole place; in the daytime, for example, assume that the tunnel mouth ambient brightness of 4000cd / m 2, speed 80KM / H, then meet the minimum requirements introduction of the length and brightness of 40 m and 80cd / m 2.
(2) adaptation period: After entering the tunnel, the driver can adapt quickly and eliminate the “black hole” phenomenon; according to the above conditions, adaptation of the length and brightness were 40 m and 80 ~ 46cd / m 2.
(3) TRANSITION: gradually adapt to the driver inside the tunnel lighting; according to the above conditions, the length of the transition section and brightness are 40 m and 40 ~ 4.5cd / m.
(4) basic sections: basic lighting inside the tunnel.
(5) Exit Section: During the day, so that the driver can gradually adapt to the exit of the light, eliminating the “white hole” phenomenon; during the night, so that the driver can see in the cave outside the linear and road obstructions eliminate the exit of the “black hole” phenomenon, the general practice is to use the street as a continuation of lighting outside the cave.
During the day, at the exit of the inlet section of the same illumination illumination, basic lighting inside the tunnel should be higher than the value of high brightness; during the night, on the contrary, should be less than the basic lighting brightness values ??inside the tunnel, when the tunnel outside the street lighting, tunnel surface brightness value of not less than 2 times the outdoor brightness value.
Second, the vehicle through the tunnel problems in the process.
1 near the tunnel problems arising in the course
Black hole phenomenon
During the day, the eyes have adapted to outdoor motor vehicle drivers up to 100000 lx cd/m2 over thousands of natural light, when the eyes go to only a few cd/m2 brightness tunnel environment, because the human eye’s perception of brightness difference is limited, appear to adapt hysteresis , you will see a black cave, while the state does not recognize them. Like to see in a bright environment cave phenomenon called black hole phenomenon. Once the black hole phenomenon, with the vehicle close to the tunnel, the driver’s visual shorten the distance, you can not drive safely. Black hole phenomenon is occurring before entering the tunnel vision problems, tunnel lighting is the most important issue. In order to prevent the occurrence of black holes, starting from the tunnel entrance within a distance sufficient to ensure the luminance, this part of the length of the braking distance than the safety of the vehicle slightly longer.
Into the tunnel, because there is a big difference in brightness outside, there is a delay adaptation, the driver can not adapt quickly tunnel vision brightness, it is difficult to see the situation inside the tunnel. To prevent this from happening, you should make the tunnel entrance brightness with reduced visual adaptation is slow, smooth transition to the brightness, the brightness should progressively be reduced, but the first one after a brightness and brightness ratio not exceeding 3:1, and 2m high these walls can not be lower than the corresponding average surface brightness brightness.
(2) through the tunnel problems occur during
Brightness in the tunnel during the day than at night lighting, high brightness, low brightness at night than during the day. Consider the long tunnel in heavy traffic automobile exhaust emissions, then because of smog-forming emissions can not dissipate quickly, the light absorption and scattering, reducing visibility, leaving the visual identification difficult, the front lights influenced by automobile exhaust, unable to meet the legibility necessary, the front surface luminance half-100m, usually two times the brightness of the lighting up of exhaust gas.
3 close to the problems that occur when the tunnel exit
Look through the export of high brightness outside, exports appear to be a bright hole, severe glare, exports became white cave, which is called white hole phenomenon; background with white hole, and motor vehicles became black silhouettes are easily identified However, in a large van with the back of cars and trucks silhouettes coincide difficult to see, in heavy traffic near the exit of the tunnel, in order to coincide with the size of the vehicle identification made lighting called exit lighting, exit lighting interval length of tens of meters.
4 night pulled out of the tunnel before the problems
Night, pulled out of the tunnel from bright to no lighting road before, outside the tunnel has become a black hole, could not see the road alignment and the presence of obstacles, this time should be just left the tunnel exit on the road, in Greater safe braking distance is roughly equivalent to a few seconds interval motor vehicle, the road for lighting, in order to achieve an appropriate level of brightness.
Third, the LED products in Tunnels
LED applications are implemented in the tunnel lighting LED light with the intensity of light entering the tunnel automatically adjust the illumination intensity intelligent dimming control system. Compared to the traditional programs to achieve energy saving 45%, and the lamp life is 6-8 times of traditional tunnel lamps, greatly reducing light loss and the cost of routine maintenance.