Under the development trend of low-carbon transportation and smart road network, solar traffic signs have become an important part of modern road safety system by virtue of their energy independence, high visibility and flexible deployment. From urban main roads to remote rural highways, these signs can run 24 hours a day without grid access, which not only reduces operation and maintenance costs, but also ensures the reliability of traffic guidance during extreme weather or power outages. However, in the face of diversified application scenarios, how to accurately match the type of sign, performance parameters and compliance requirements has become a key issue when purchasing.
Speed limit signs, solar powered no parking signs, stop and yield signs.
The message must be conveyed in a mandatory manner, and the LED lights need to be continuously and stably illuminated to ensure that they are clearly visible at all times. For example, the speed limit sign at the entrance of the city school needs to be matched with flashing function to strengthen the warning effect during the school hours; the no parking sign at the service area of the highway needs to be luminous on both sides to avoid the vehicles from different directions to avoid missing to see when they are driving in.
sharp turns, steep slopes, construction sections, pedestrian crossing areas.
The warning color scheme of yellow background + black pattern is mostly used, with dynamic flashing lights to enhance the attention. Such as mountainous highway warning signs for sharp bends, need to be set up in front of the bend at 100-200 meters, LED flashing frequency is recommended to be controlled at 1-2 times / second, not only to avoid visual fatigue, but also to effectively attract the attention of drivers.
Directional signs, exit warning signs, construction detour signs.
Text and arrows need to be concise and clear to avoid information overload. For example, the direction signs of highway hubs need to adopt three-dimensional layered design, differentiate the main line and ramp information with different colors, and at the same time, ensure that the LED backlighting is uniform to prevent the local dark areas from affecting readability at night.
The LED brightness of main road signs should reach 5000-8000mcd to ensure that it is clearly visible 200 meters away at night; rural roads can be appropriately reduced to 3000-5000mcd to save energy.
In dusk or rainy day environment, stand at the target distance to observe the sign, if you need to squint or concentrate to recognize the content, then you need to enhance the brightness or increase the reflective film to assist (such as engineering-grade reflective film can reflect the light of the headlights in non-lighting state).
Font height = observation distance (meters) × 0.03. For example, for a speed limit sign with a sight distance of 100 meters, the font height should be not less than 30cm, and the ratio of character width to height is recommended to be 1:1.2 (e.g., the number “40” km/h).
Circular speed limit sign diameter recommended 60-100cm (urban roads take the small value, high speed take the large value), triangular warning signs side length of not less than 70cm, to ensure that the driver has enough time to react under normal speed.
Monocrystalline silicon panel conversion rate > 20%, suitable for areas with insufficient light (such as rainy and foggy mountainous areas); polycrystalline silicon panels cost-effective, stable performance in areas with average daily light ≥ 4 hours.
Take 10W LED light working 12 hours a day as an example, the average daily power consumption is 120Wh, the solar panel power needs to meet the average daily power generation more than 1.5 times (i.e., ≥15W), and set aside 20% redundancy to deal with cloudy and rainy days.
Li-Fe phosphate batteries have a life span of 5-7 years, excellent low-temperature resistance (-20℃ can work normally) and are suitable for northern regions; lead-acid batteries are low-cost but require regular checking of the electrolyte and are more suitable for warmer environments in the south.
3-5 Days of rainy day power needs to be reserved. For example, for a solar traffic sign with average daily power consumption of 120Wh, the battery capacity should be ≥600Wh (e.g. 12V/50Ah lithium battery) to ensure that it can still operate normally under continuous rainy weather.
It should reach IP65 or above (it can prevent the intrusion of heavy rain), the solar traffic sign should pass the -30℃ low temperature test in the northern region, and it should withstand 60℃ high temperature and strong ultraviolet irradiation in the southern region.
The frame is made of aluminum alloy or stainless steel, the surface is treated with fluorocarbon spraying (additional anti-salt spray coating is required in coastal areas), and the panel is made of polycarbonate, which has an impact strength of 200 times that of ordinary glass.
The ink on the surface of the solar powered traffic sign should pass 1000 hours UV aging test, the color fading degree △ E ≤ 5 (imperceptible to the naked eye), to avoid long-term exposure to the sun leading to blurring of the warning message.
When vehicles or pedestrians approach, the sign automatically enhances the brightness, and after leaving, it resumes low-power mode, which is more than 30% energy-saving compared with the constant light mode, especially suitable for low-traffic scenarios such as rural roads.
Built-in photoresistor, automatically adjusts the LED power according to the environmental brightness, avoiding the waste of power during the daytime accidental lighting.
Through 4G or LoRa module, transmit data such as battery power and LED working status to the management platform, and automatically alarm when abnormal (e.g. push reminders when power is lower than 20%).
Construction road signs can be remotely switched to display dynamic information such as “construction ahead” and “slow down”, eliminating the need for manual on-site replacement and improving emergency response efficiency.
It should comply with GB 5768 “Road Traffic Signs and Markings”, the optical performance of LED has passed CQC certification, and the grade of reflective film should reach GB/T 18833 above the second level standard.
European and American markets need to meet MUTCD (U.S. Traffic Signs Standard) or EN 12368 (European Reflective Material Standard), and pass CE, FCC and other safety certificates.
For example, red represents prohibition (e.g., no passing sign), yellow represents warning (e.g., attention to children sign), blue represents instruction (e.g., straight ahead sign), and the shapes and colors must strictly follow the national standard to avoid confusion among drivers.
North hemisphere towards the south, south hemisphere towards the north, tilt angle for the local latitude ± 15 ° (such as 30 ° north latitude area, the tilt angle is recommended to 30 ° - 45 °), to ensure that the maximum amount of light received throughout the year.
1.8-2 Meters for solar powered warning signs (to avoid blocking by pedestrians), 2.5-3 meters for solar powered speed limit signs (line-of-sight height for large vehicles), and keep away from the shade of trees or shaded areas of buildings.
Panels covered with nano-titanium dioxide coating, rainwater can automatically wash away dust, maintenance cycle extended to 6-12 months.
LED light sets, batteries, and controllers are designed with independent slots, which can be replaced individually in case of failure without overall disassembly, reducing the maintenance cost by more than 50%.
Scene positioning: city road/rural highway/construction temporary use/highway?
Functional screening: regulatory class (speed limit/prohibit) → warning class (sharp bend/school) → information class (direction/detour).
Light assessment: average daily light <4 hours → select monocrystalline silicon panel + high-capacity lithium battery; sufficient light → polycrystalline silicon + conventional battery.
Intelligent demand: Is remote monitoring or dynamic information switching required? Prioritize models with IoT modules when budget allows.
Compliance verification: Confirm local traffic standards and request certification reports (e.g. GB 5768 test report, LED light efficiency test report).
Although the initial purchase cost of solar-powered traffic signs is 20%-30% higher than that of traditional grid signs, the investment can be recovered in 3-5 years through electricity savings and low maintenance costs (at an average of 10 hours of daily operation, a single sign will save about $5,000 in annual electricity costs). What's more, its reliability and intelligent management capability in extreme weather can significantly improve road safety. In the future, with the integration of AI and IoT technology, a new generation of solar signs with violation capture linkage and traffic data analysis functions will become the trend, and the reserved interface and expandability when purchasing can further enhance the system's full life cycle value.
