Traditional road markings rely on headlight reflection for visibility, which has obvious limitations in low-light environments such as at night or in foggy conditions. Solar road studs overcome this bottleneck through a “solar energy conversion + active lighting” model. Their core performance metric—luminous intensity (unit: millicandela per square meter, mcd)—directly determines drivers' visual perception distance and reaction time. According to statistics from the European Road Safety Organization, installing solar road studs that meet brightness standards can reduce nighttime curve accident rates by 47%. How to scientifically set brightness thresholds based on variables such as road conditions, vehicle speed, and environment has become a key issue in modern intelligent transportation systems.
Energy Collection Layer: Monocrystalline silicon/amorphous silicon solar panels, with an average of 4 hours of sunlight per day sufficient to support 12 hours of continuous power supply
Energy storage layer: Lithium-polymer batteries with a capacity of 220–500 mAh, supporting a wide temperature range of -30°C to 70°C.
Light output layer: High-brightness LED chips with wavelengths concentrated between 450–650 nm (blue/white/yellow spectrum), with a light decay rate of ≤10% per 1,000 hours.
|
Type |
Material Composition |
Typical Brightness Range |
Application Scenarios |
Technical Advantages |
|
High-strength Road Studs |
Aluminum Alloy + Tempered Glass |
5000–7000 mcd |
Highways, Mountainous Curves |
Crush-resistant (load capacity ≥20 tons), strong weather resistance |
|
Lightweight Road Studs |
ABS Engineering Plastic |
3000–5000 mcd |
Urban Roads, Pedestrian Paths |
Weight <500g, 30% reduction in installation costs |
|
Smart Adjustable Brightness Studs |
Composite Materials + Chips |
2000–8000 mcd (Dynamic) |
Tunnel Entrances/Exits, Weather-Sensitive Sections |
Supports light/rain sensing automatic dimming, wireless cluster control |
When vehicle speed is 100 km/h:
5000 mcd brightness: Driver visibility distance 150 meters, reaction time 5.4 seconds (safety threshold ≥ 3 seconds)
3000 mcd brightness: Visibility distance reduced to 80 meters, reaction time only 2.88 seconds (below safety critical value)
2000 mcd brightness: Visibility distance less than 50 meters; when emergency braking distance (39 meters) and reaction distance (27.8 meters) are combined, the accident probability increases by 2.3 times
|
Weather Type |
Brightness Decay Ratio |
Actual Effective Brightness (using 5000 mcd as an example) |
Safety Hazard Level |
|
Clear Night |
0% |
5000 mcd |
Low |
|
Light Rain Weather |
25% |
3750 mcd |
Medium |
|
Heavy Fog (Visibility 50 m) |
45% |
2750 mcd |
High |
|
Heavy Rain + Dust |
60% |
2000 mcd |
Extremely High |
Mainline highways: ≥5500 mcd (visible distance ≥120 meters at 100 km/h)
Ramp curves: ≥7000 mcd (to compensate for visual displacement caused by centrifugal force)
Ordinary roads: 3000–5000 mcd
Fog zone special standard: ≥6000 mcd (in conjunction with fog light interlocking system)
Rainy night mode: ≥6500 mcd (must pass IPX7 waterproof testing)
Ice and snow sections: ≥5000 mcd (with anti-icing coating)
L = K1×V + K2×E + K3×R
L: Target brightness (mcd)
K1: Vehicle speed coefficient (0.05–0.1, 0.1 at 120 km/h)
V: Design vehicle speed (km/h)
K2: Environmental coefficient (0.8 for clear weather, 1.5 for heavy rain, 2.0 for dense fog)
E: Base brightness (3000 mcd)
K3: Road coefficient (1.0 for straight roads, 1.8 for sharp curves, 1.5 for slopes)
R: Risk correction value (accident-prone sections +1000 mcd)
Principle: For every 10 km/h increase in vehicle speed, the human eye's visual persistence time decreases by 0.1 seconds, requiring an additional 500 mcd compensation
Case study:
Urban roads (60 km/h): 3000 mcd is sufficient to meet requirements
National highways (80 km/h): 4000 mcd is required to maintain a 2-second reaction time
Expressways (120 km/h): 5000 mcd is the minimum safety threshold
When airborne particle concentration exceeds 0.3 mg/m³, light scattering coefficient increases by 40%, requiring 7000 mcd of intense light to penetrate
Road surface water film reflection causes effective brightness to decrease by 35%, requiring an additional 2000 mcd above the standard value
Suspended particles significantly absorb short-wavelength light (blue light), so it is recommended to use yellow-red light (5500 mcd) in the 600-650 nm range.
Sharp curves: 7000 mcd road studs should be installed on the outer side of the curve to form a continuous light guidance trajectory, counteracting the visual displacement caused by centrifugal force.
Tunnel entrances/exits: Brightness gradients should be set in the light-dark transition zone (8000 mcd at the entrance → 5000 mcd inside the tunnel) to mitigate the “black hole/white hole effect”
Slope undulations: Additional 6000 mcd road studs should be installed at the turning points of uphill/downhill slopes to indicate slope changes (for every 100-meter increase in elevation, light intensity should be increased by +500 mcd)
Prefer high-efficiency models:
Color temperature: 5000-6500K (white light, better penetration than warm light)
Luminous flux: Single LED ≥1000 mcd (e.g., Cree XHP50.2 series)
Use Fresnel lenses: improve light concentration efficiency by 40%, control beam angle between 15°-30° (balancing visibility range and penetration)
Parabolic reflector cup: light reflectivity ≥95%, avoid stray light interfering with driver vision
Real-time data collection: illuminance, rainfall, and traffic flow data
Dynamic response: automatically increases brightness by 2000 mcd in foggy conditions and reduces brightness by 1000 mcd at night in clear conditions for energy savings
Cluster control: supports synchronized brightness adjustment of road studs within a 500-meter range
High/low temperature cycling: -40°C to 80°C, brightness decay ≤5% after 1000 cycles
Waterproof and dustproof: IP68 rating (Operates normally after being submerged in water at 1 meter depth for 24 hours)
After continuous operation for 1000 hours, brightness retention rate ≥90% (complies with GB/T 24827-2015)
Withstands a 10-ton truck rolling over at 60 km/h, with no shell cracking and brightness fluctuation ≤±5%
Central median strip: 5,000 mcd white light road studs, spaced 15 meters apart
Effect: In a real-world test on a provincial highway, nighttime lane deviation rate decreased by 62%
Emergency lane edge: 6,000 mcd yellow flashing road studs (1 Hz frequency)
Principle: Flashing light improves visibility by 3 times compared to constant light, effectively guiding faulty vehicles to the parking area
50 meters before entering the curve: 7000 mcd red-yellow alternating flashing road studs (red → yellow gradient)
At the apex of the curve: 6,500 mcd white constant-on road studs, forming a continuous light track
30 meters after exiting the curve: 5,000 mcd white road studs, restoring conventional guidance
6,000 mcd road studs installed every 100 meters, combined with oscillating lane markings, visually indicating changes in slope
Both sides of the crosswalk: 4000 mcd white road studs (constant-on mode)
Turn lanes: 3500 mcd yellow road studs (flashing in sync with traffic lights)
Effect: After renovation of a major urban artery, nighttime pedestrian accidents decreased by 53%
3000 mcd warm white road studs (4000K color temperature) to reduce glare while meeting 200-meter visibility requirements
The brightness settings for solar-powered road studs are not a single numerical standard but require the establishment of a three-dimensional dynamic model of “road conditions-environment-traffic.” The ideal brightness range should be between 3000 and 7000 mcd, achieved through the following pathways:
Establish a regional brightness database: classify brightness standards by climate zone (humid/arid/foggy) and terrain (plains/mountains/plateaus)
Promote intelligent dimming technology: New projects may be equipped with environment-sensing dimming systems to achieve automatic brightness compensation.
Strengthen full lifecycle management: Conduct brightness decay inspections quarterly, and perform luminous efficiency calibration after accumulating 5,000 hours of operation.
Q1: What is the brightness decay cycle for solar road studs?
A1: High-quality products have an annual decay rate of ≤5% under standard conditions, with cumulative decay not exceeding 25% over five years.
Q2: How can light interference caused by excessive brightness be avoided?
A2: By controlling the beam angle to ≤30° through optical design and using intelligent light-sensing technology to avoid glare for oncoming vehicles.
Q3: Does brightness enhancement during rainy or foggy weather increase energy consumption?
A3: Yes, but modern energy storage technology enables brightness enhancement to 2000 mcd while maintaining a runtime of 72 hours (three consecutive days of rainy weather).
