Road studs, as key facilities for guiding road traffic, whether they are reflective night signs or solar-powered studs that actively emit light, directly affect the safety of vehicle travel and the efficiency of road traffic. In scenarios such as highways, municipal roads, and tunnels, road studs need to withstand multiple tests such as vehicle rolling, rain erosion, and temperature changes for a long time. The stability of their performance is of vital importance.
The inspection standards are precisely the "yardstick" for measuring whether the road studs meet the usage requirements. Road studs that do not meet the standards may encounter problems such as loose installation, failed reflection, and damaged shells. In mild cases, they may lose their guiding function; in severe cases, they may cause traffic accidents. Especially for active road studs like solar-powered road studs, in addition to basic performance, the reliability of solar modules and LED light sources is a key point of inspection. Therefore, a thorough understanding of the road stud inspection standards is not only a necessary step in project acceptance but also the core basis for choosing high-quality road stud products.
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Road stud inspection is not an assessment of a single indicator, but rather focuses on four core dimensions: stability, reflectivity, impact resistance, and material durability. These four dimensions jointly determine the service life and safety value of road studs. At present, widely applied international standards such as the European EN 1463-2:2021 have made detailed regulations on the detection methods and qualification thresholds of these four dimensions, becoming an important reference for the global production and inspection of road studs.
Among them, stability ensures that the road studs "do not fall off", reflectivity ensures that they "are visible", impact resistance ensures that they "can withstand", and material durability ensures that they "last long". For solar-powered road studs, on the basis of these four major dimensions, an additional "energy component reliability" test should be added to form a "4+1" specialized testing system.
If the road studs are not installed firmly, they are prone to loosening and falling off under the repeated rolling of vehicles. Not only will they lose their guiding function, but they may also become obstacles on the road surface. Stability and installation testing mainly focus on 3 core links:
By using professional adhesion testing instruments, a tensile force perpendicular to the road surface is applied to test the bonding strength between the road studs and the road surface. According to the EN 1463-2:2021 standard, the adhesion of the road studs should be ≥1.5MPa, and there should be no obvious displacement or detachment marks of the road studs after testing. In actual testing, it is also necessary to sample and check the adhesion differences of different road surface materials (asphalt, cement) to ensure that they all meet the requirements in different scenarios.
The cleanliness and dryness of the road surface are the key prerequisites affecting adhesion. When conducting the inspection, it is necessary to confirm that the installation area is free of oil stains, dust and water accumulation. If there are cracks or depressions on the road surface, they need to be repaired and leveled in advance. For instance, when installing solar-powered road studs in tunnels, if there is residual construction dust on the road surface, it will lead to a reduction in the bonding area between the studs and the road surface, and the adhesion will drop by more than 30%.
Road studs must be positioned strictly in accordance with the road design drawings, with a longitudinal spacing error of no more than 5cm and a lateral offset of no more than 3cm. On special sections such as curves and slopes, it is also necessary to check whether the road studs match the driving trajectory to avoid incorrect direction guidance due to positional deviations.
The reflectivity of road studs directly determines the visibility at night. The inspection should cover 3 major requirements: "environmental adaptability, strength compliance, and surface integrity".
A humid environment is a "key test" for reflectivity - rainwater will cover the reflective surface, reducing the reflection efficiency. When conducting the detection, it is necessary to simulate a rainfall scenario (rainfall ≥2mm/min), and use a retroreflective marking line measuring instrument to measure the reflective intensity at three distance points of 100m, 50m, and 30m. According to the standards, the reflective intensity of the road studs in a humid state should be ≥ 60% of that in a dry state, and the active luminous intensity of the LED of the solar-powered road studs should be ≥200cd (candela).
The detection must be carried out in a darkroom environment. The light source Angle simulates the vehicle headlight (incident Angle 15°), and the receiving Angle simulates the driver's line of sight (observation Angle 0.2°). The reflective intensity of ordinary retroreflective road studs in a dry state should be ≥300mcd ·lx⁻¹· m⁻². The LED light emission of solar road studs should remain stable, without flicker or brightness attenuation (the brightness change after continuous lighting for 24 hours should be ≤10%).
The reflective film or reflective beads must be free from wear, scratches and dirt. If the reflective surface has damage with a diameter of ≥2mm or the area covered by dirt is ≥10%, it will be judged as unqualified. For solar-powered road studs, it is also necessary to check whether the light-transmitting cover is clear, without yellowing or fogging (the light transmittance should be ≥90%).
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Road studs need to withstand vehicle rolling, impact and environmental erosion. The inspection needs to simulate long-term usage scenarios:
Place the road studs in a salt spray chamber (5% NaCl concentration, 35℃ temperature) for continuous testing for 48 hours. After taking them out, check that the outer shell is free of rust, the coating is free of peeling, and the terminal blocks of the solar-powered road studs are free of oxidation.
After cycling 10 times between -30℃ (low temperature) and 60℃ (high temperature) for 12 hours each time, the road studs showed no cracking or deformation, the solar panels did not bulge, and the LED lights could light up normally.
A drop weight impact testing machine is used. A 5kg hammer is freely dropped from a height of 1.5m to impact the center of the top of the road studs. After inspection, the road studs should have no cracks or fragments falling off, and the base should be firmly connected to the outer shell. For solar-powered road studs, it is also necessary to check whether the solar panels short-circuit after impact and whether the LED lights can still work normally.
Check that the surface is free of scratches and cracks, and the photoelectric conversion efficiency is ≥18% (under standard conditions).
During continuous rainy weather (simulating three days without sunlight), the solar road studs need to rely on energy storage batteries to maintain their light emission, and the brightness does not decrease significantly. In the charging efficiency test, under standard sunlight (1000W/m²), the 4-hour charging volume needs to meet the requirement of continuous light emission for 12 hours.
The quality of materials and structural design determine the basic performance of road studs. The inspection should focus on "flatness, anti-slip property, and structural rationality".
The base should be made of high-strength engineering plastics (such as PC+ABS) or metal materials, with a flatness tolerance of ≤0.5mm/m. When conducting the inspection, use a straightedge to closely adhere to the surface of the base, and insert a feeler gauge into the gap. The maximum gap should be no more than 0.3mm to prevent uneven force distribution after installation due to an uneven base, which could shorten the service life.
The top of the road studs should have anti-slip patterns, with a depth of no less than 1mm and a width of no less than 2mm. The friction coefficient of the road stud surface was tested by the friction coefficient tester to be ≥0.6 in dry condition and ≥0.4 in wet condition, preventing skidding when vehicles pass over it (especially on rainy or icy roads).
The compressive strength of the road studs should be ≥100kN (kilonewtons), simulating the rolling of a heavy truck (with an axle load of 13t). There should be no permanent deformation after the test. The energy storage battery compartment of the solar-powered road studs should be well sealed. After the water immersion test (with a water depth of 1 meter and soaking for 2 hours), there should be no water ingress and no short circuit in the battery.
The detection of road studs requires dual verification through "laboratory-specific tests + on-site road tests". Only by combining the two can the performance be fully reflected.
|
Test Type |
Test Item |
Test Equipment |
Standard Requirements |
|
Laboratory Test |
Reflectivity intensity |
Retroreflective marking line measuring instrument |
≥300 mcd·lx⁻¹·m⁻² (dry conditions); ≥180 mcd·lx⁻¹·m⁻² (wet conditions) |
|
Laboratory Test |
Impact resistance |
5 kg drop weight impact testing machine |
Drop height 1.5 m; no damage |
|
Laboratory Test |
Salt spray corrosion resistance |
Salt spray chamber |
No rust and no coating peeling after 48 hours |
|
On-site Test |
Road installation stability |
Tensiometer, tape measure |
Adhesion ≥1.5 MPa; position error ≤5 cm |
|
Road Field Test |
Durability (1 year) |
Regular inspection (once a month) |
No peeling; reflective intensity attenuation ≤20% |
|
Road Field Test |
Solar-powered road stud battery life |
Battery life monitor |
Able to emit light normally even after three days of rain |
Laboratory testing focuses on "precise controllability" and can eliminate external interference. Road field testing focuses on "real scenarios" and can reflect the performance of road studs in actual traffic flow and environmental changes. For instance, a certain batch of solar-powered road studs met the reflective intensity standards in laboratory tests. However, during field tests, due to the excessively high road surface temperature (over 60℃ in summer), the LED light intensity declined too rapidly. Eventually, the heat dissipation structure was adjusted to meet the standards.
At present, the most authoritative standard system for road stud testing worldwide is the European EN 1463 series, which is divided into two parts: EN 1463-1:2021 and EN 1463-2:2021, covering "Product Specifications" and "Testing Methods".
Clearly define the basic requirements for the material, size, color, reflective performance, structural strength, etc. of the road studs. For instance, the height of the road studs should be no more than 25mm (to avoid affecting vehicle traffic), the width should be no less than 80mm (to ensure stability under compaction), and the color should comply with the CIE (International Commission on Illumination) chromaticity coordinate standards.
Specify in detail the testing procedures for each performance item, such as the light source parameters for the reflection intensity test, the hammer weight and height for the impact resistance test, and the concentration and temperature for the salt spray test, to ensure that the test results from different laboratories are comparable.
In addition to European standards, China's GB/T 24725-2020 "Glass Beads for Pavement Markers" and the United States' ASTM D4061 "Standard Specification for Retroreflective Pavement Markers" are also commonly used for regional market testing. However, due to its comprehensive coverage and rigorous testing, the EN standard has become a "universal threshold" for the global export of solar road studs.
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The color of the road studs is not chosen randomly but conveys road information through "color coding". The inspection must ensure that the color is accurate and without deviation.
|
Road Stud Color |
Road Position |
Function/Role |
Color Standard (CIE Chromaticity Coordinates) |
|
Red |
Left edge of the road |
Indicates the left boundary of the lane; crossing is prohibited |
x=0.645±0.015, y=0.335±0.015 |
|
Amber |
Central divider (two-way lanes) |
Indicates the boundary of the opposite lane; warns to give way |
x=0.540±0.015, y=0.430±0.015 |
|
White |
Lane boundary line (same-direction) |
Indicates the boundary of lanes in the same direction; guides driving |
x=0.313±0.015, y=0.329±0.015 |
|
Blue |
Emergency lane boundary |
Indicates the emergency passage; for emergency use only |
x=0.150±0.015, y=0.060±0.015 |
Color detection should be carried out under a standard light source (D65 light source, color temperature 6500K). A spectrophotometer should be used to measure the chromaticity coordinates, and at the same time, the color uniformity (color deviation of the same batch of road studs ≤5%) should be checked, with no fading or color difference. For instance, if the color of red road studs turns orange (x<0.630) after long-term exposure to the sun, they are judged as substandard and need to be replaced with pigments or coatings with better weather resistance.
The inspection standards for road studs are a full-process quality control from "product leaving the factory" to "road surface application". For both the engineering party and the purchaser, paying attention to the testing standards is not only a compliance requirement but also a responsibility for traffic safety. As a new generation of road stud products, solar-powered road studs have more prominent testing standards that emphasize both energy conservation and reliability: high-quality solar-powered road studs must pass strict anti-corrosion and anti-impact tests. The solar modules have high conversion efficiency, and the LED light sources are stable and durable.
Choosing high-standard solar-powered road studs means choosing a "safe, durable and energy-saving" traffic solution. If you need to know more about the solar-powered road stud inspection process or obtain a customized solar-powered road stud product solution, please feel free to consult NOKIN at any time!
