Since the first traffic equipment with road traffic signal indication function appeared in 1868 in Britain, the road traffic signal light had undergone three changes. The first generation of traffic signal "lights" can only be called as traffic signal indicators in the real sense. Some use kerosene lamps as light sources, while others use signs as traffic indicators; Since Edison invented the incandescent lamp, the traffic signal light has realized the second generation in the true sense of "unified form". The second generation of traffic lights has experienced more than 100 years. Until the late 1990s, with the gradual maturity of semiconductor lighting technology, the third generation of energy-saving and efficient traffic lights - LED traffic lights were widely used. The red, yellow and green traffic lights have also become a permanent sign on the global roads.
The application of traffic lights in China began in the British Concession in Shanghai in 1923. After the founding of New China, the traffic lights gradually be used widely. Now the government is also promoting the construction of transportation. For the R&D, production and sales enterprises of traffic safety facilities such as road traffic lights and signal machines, if they can seize the opportunity of "intelligent transportation" development, they may usher in another spring of industry development.
The promotion of construction of a transportation means that new requirements have been put forward for the research and development ability, quality management, and integration ability of the participants. They have the innovation gene and lead the technological trend of the industry. In terms of enterprise management, enterprises that dare to invest will occupy the market competition; A new generation of transportation intelligent products which integrates advanced technologies such as big data, cloud computing, 5G mobile communication network, driverless driving, high-speed image detection and analysis, artificial intelligence, edge computing, etc., provides a huge market for brave pioneer.
In order to regulate the production of traffic lights, China has set the GB 14887 standard for road traffic lights, and the reliability test standards involved are as follows:
1. High temperature resistance
The signal lamp shall be tested for 8h under the working condition under the ambient temperature of 80 ℃± 2 ℃. During and after the test, the signal light shall work normally. Check that the light shell, shade and other parts shall be free of deformation, cracking, gloss change and other defects, and the sealing part shall be free of cracking.
2. Low temperature resistance
After the signal lamp is placed at an ambient temperature of - 40 ° C ± 3 ° C for 2 hours, the power supply of the signal lamp shall be switched on, and the signal lamp shall be able to light normally. The signal lamp shall withstand a test for 4 hours under working condition. During and after the test, the signal lamp shall work normally. Check that the light shell, shade and other parts shall be free of deformation, cracking, gloss change and other defects, and the sealing shall be free of cracking.
3. Hygrothermal performance
The signal lamp shall be subjected to the test for 48 h under the working condition under the ambient temperature of 40 ℃± 1 ℃ and humidity of 93% ± 2%. The signal lamp shall work normally during and after the test. The insulation resistance, dielectric strength and leakage current performance shall be tested immediately after the test.
4. Salt spray resistance
The traffic light is subjected to 96 h salt spray test under the following conditions: the temperature of the test chamber is 35 ℃± 2 ℃, the mass percent concentration of salt spray solution is 5% ± 0.1%, and the salt spray sedimentation rate is 1.0 mL/(h · 80 cm ²)~ 2.0mL/(h，80cm ²), Spray every 45min for 15min. Check the number of rust points within 10 000 mm ² The number of rust spots on the area shall be less than 8. (Note: The salt spray test is only applicable to metal housing signal lamps.)
If the signal lamp is exported to foreign countries, it shall comply with the EU EN12,368 certification. The requirements for temperature resistance of traffic lights are as follows:
Class A +60°C to-15°C
Class B +55°C to-25°C
Class C +40°C to-40°C