What are the advantages and disadvantages of LED traffic lights?

Japan's first traffic light was installed at the Hibiya intersection in Tokyo in 1930 (Showa 5). The following year, 1931 (Showa 6), three-color automatic traffic lights were installed at 34 locations, including the Ginza-4-chome intersection and Kyobashi intersection in Tokyo, and became popularized after World War II. By the way, LED traffic lights (hereinafter referred to as LED traffic lights) have been installed in Aichi and Tokushima prefectures since 1994 (Heisei 6).

Looking at the current status of the installation of LED traffic lights in Japan, the National Police Agency announced the penetration rate of vehicles in late March 2020 (the total number is the first year of Reiwa), there are about 1.27 million lights and about 10,200 pedestrian lights, a total of about 230 Ten thousand lights, of which about 60.7% (about 63.1% of vehicles) are LED signal lights. , pedestrians are about 57.8%)”.

Tokyo, which has the largest number of LED traffic lights installed, has a penetration rate of 100%. Fukuoka Prefecture (99.8%), Nagasaki Prefecture (98.5%), and Okinawa Prefecture (92.9%) are all in progress.

Summarize the characteristics of the lighting part of LED traffic lights. The filament emits light like a light bulb and radiates light to the surroundings through the lens, while the LED itself emits light and develops color. The luminous intensity of the lamp itself is uniform and the visibility is good.

Bulb-type signal lights that are color-coded with lenses appear to be lit (called "pseudo-illumination") when exposed to sunlight, even if not actually lit, making it difficult to see due to angle and amount of sunlight There is a case .

On the other hand, in the LED type, as described above, the LED itself of the light source develops color, and the direction of light irradiation is narrowed (high directivity), so that it is easy to see (high visibility). have.

In addition, the power consumption of the LED type is about one-sixth of that of the light bulb type (bulb type 70W, LED 15W), so it has the advantages of high energy saving effect and low electricity bill. The lifespan of the bulb type is about half a year to one year, while the lifespan of the LED type is 6 to 8 years, which is advantageous in terms of maintenance.