R&D and Manufacturing of Smart Road Traffic Safety Facilities
Founded as the First In-House Venture of the Korea Road Traffic Authority
An LED traffic signal with automatic luminance control based on a precision light sensor. It measures the actual brightness at the intersection and adjusts signal brightness on its own. Installs on existing signal controllers with no additional wiring.
With Precision Light-Sensing Dimming Technology
Why it matters
Brightness set for full daylight causes driver glare at night and light-pollution complaints from nearby homes. The need for dimming has long been recognized, but cheap sensors are inaccurate, precision light meters are expensive, and controller-based half-wave dimming requires changes to other safety equipment, so none of these approaches spread in the field.
How it works
A light sensor inside a cubic diffuser box measures brightness from two or more directions and derives one representative value for the intersection. Sun or a single nearby light source cannot skew it.
The red, amber, arrow and green signals on the same approach are dimmed together from that representative value, so there is none of the uneven brightness that comes from fitting a sensor to each signal.
A Sensor SMPS inside the signal combines the sequentially switched lamp supplies through diode OR-ing to create continuous power. Existing controllers and cabling stay as they are.
If the sensor unit fails, the signal simply lights at normal daytime brightness. Units are currently supplied with two-level day/night control under the Police Agency standard; if the standard adds finer levels, they can switch to multi-level control without changing the core technology.
Especially effective at intersections near homes, where night glare and light pollution complaints are common.
One representative illuminance value sets the brightness of every device on the pole together.
| Item | Standard signal | Half-wave dimming | CdS sensor signal | Light-Road |
|---|---|---|---|---|
| Dimming method | None | Uses half of the supply cycle | Individual sensor per signal | Automatic, from measured ambient light |
| Works without modifying other equipment | N/A | No (modification required) | Yes | Yes |
| Uniform control of one approach | No | Yes | No (uneven brightness) | Yes |
| Real-time response | No | No | Yes | Yes |
| Sensor accuracy (f1′ within 8%) | N/A | N/A | Fails (about 20–60%) | Meets (7.9%) |
Watch
See the precision light-sensing, self-dimming LED traffic signal on video.
If the video does not play, watch it on YouTube.
Testing & certification
| Item | Result | Lab · Report no. |
|---|---|---|
| Police Agency standard (R02): compatibility, environment, durability, electrical, optical, dimming | Pass on all items | KIEL KIEL2607-F07853–F07858 |
| EMC: conducted noise, radiated noise, lightning impulse | Pass | E26KR-2127, KIEL2606-KF07134–KF07139 |
| Light sensor spectral mismatch f1′ | Sensor + diffuser 7.9% / sensor 6.2% | 260416AJ65, JICS-703-N260001 |
| Intersection group control | Three colors controlled by one sensor | Korea Road Traffic Authority KOROAD-G2026-B21-0001 |
| Housing: tensile strength, impact strength, heat deflection, flammability | 62.5 MPa, 29 kJ/m², 93 °C, V-0 | CT25-087120K |
| Cut-off impedance (limit below 10 kΩ) | 7.2 kΩ | KIEL |
| Equipment conformity registration, direct production certificate | Held | Direct production No. 2026-0447-00385 |
Documents are issued in Korean. Click to enlarge.
Korean Patent No. 10-2785102Smart traffic signal display system at intersections
Korean Patent No. 10-3010374 (co-owned with Seyang Tech)Illuminance-linked group dimming control system
Broadcasting & communication equipment registrationR-R-LRd-LROAD-SVR-01 · National Radio Research Agency
Direct production certificateNo. 2026-0447-00385 · Traffic signals
Factory registration certificateTraffic signal device manufacturing · Osan
Public procurement bidder registrationPublic Procurement Service (KONEPS) · Goods
Police Agency standard (R02) test reportKIEL KIEL2607-F07853
EMC test reportKIEL KIEL2606-KF07135
Korea Road Traffic Authority test reportPower and luminance tests KOROAD-G2026-B21-0001
Operated in a real intersection environment for about 35 days, from July 25 to August 31, 2024. Measured light levels matched sunrise and sunset times from the Korea Astronomy and Space Science Institute, and the system ran reliably in clear, cloudy and rainy weather.
In subject glare ratings (5 = very glaring, 3 = appropriate), daytime brightness at night scored 4.1–4.5, while dimming to 42% of daytime brightness scored 3.2, rated appropriate.
Economics
Estimate for one pole with three 4-color vehicle signals, one 2-color pedestrian signal, one red/green countdown pedestrian unit and two light sensor units.
LED life extension is counted conservatively at 30%, rather than the theoretical ~3.5× from lower drive current.
No dimmingSame brightness and power day and night.
Two-level day/nightCurrent supply mode. Saves energy by dimming at night.
Real-time controlAvailable on the same hardware once the standard adds finer levels.
Adoption
Search the KONEPS catalog by item ID or "Light-Road" for specifications and pricing.
Go to KONEPS| Item ID | Model | Configuration |
|---|---|---|
| 26412896 | LROAD-SVR-01 | Vehicle signal (red) |
| 26412897 | LROAD-SVY-01 | Vehicle signal (amber) |
| 26412898 | LROAD-SVA-01 | Vehicle signal (green arrow) |
| 26412899 | LROAD-SVG-01 | Vehicle signal (green) |
| 26412888 | LROAD-SVRYA-01 | Vehicle signal (red / amber / green arrow) |
| 26412889 | LROAD-SVRYG-01 | Vehicle signal (red / amber / green) |
| 26412890 | LROAD-SVRYAG-01 | Vehicle signal (red / amber / green arrow / green) |
| 26412894 | LROAD-SVYY-01 | Warning signal (amber / amber) |
| 26412895 | LROAD-SVYYY-01 | Warning signal (amber / amber / amber) |
| 26411840 | LROAD-SVRR-01 | Warning signal (red / red) |
| 26412891 | LROAD-SPR-01 | Pedestrian signal (red) |
| 26412892 | LROAD-SPG-01 | Pedestrian signal (green) |
| 26412893 | LROAD-SPRG-01 | Pedestrian signal (red / green) |
| 26411841 | LROAD-SVR-01(Y) | Vehicle signal (red) |
| 26411842 | LROAD-SVY-01(Y) | Vehicle signal (amber) |
| 26411843 | LROAD-SVA-01(Y) | Vehicle signal (green arrow) |
| 26411844 | LROAD-SVG-01(Y) | Vehicle signal (green) |
| 26411845 | LROAD-SVRYA-01(Y) | Vehicle signal (red / amber / green arrow) |
| 26411846 | LROAD-SVRYG-01(Y) | Vehicle signal (red / amber / green) |
| 26411847 | LROAD-SVRYAG-01(Y) | Vehicle signal (red / amber / green arrow / green) |
| 26411852 | LROAD-SVYY-01(Y) | Warning signal (amber / amber) |
| 26411853 | LROAD-SVYYY-01(Y) | Warning signal (amber / amber / amber) |
| 26411854 | LROAD-SVRR-01(Y) | Warning signal (red / red) |
| 26411848 | LROAD-SPR-01(Y) | Pedestrian signal (red) |
| 26411849 | LROAD-SPG-01(Y) | Pedestrian signal (green) |
| 26411850 | LROAD-SPRG-01(Y) | Pedestrian signal (red / green) |
| 26412688 | LROAD-SLC-01 | Part: light sensor unit |
Search KONEPS by item ID or "Light-Road" to purchase.
Compatible with existing signal controllers; installation cost is the same as a standard signal. One sensor unit each for vehicle and pedestrian signals per pole is typical. Avoid spots lit directly by artificial light.
Free for 3 years. From years 3 to 10, only parts and travel at cost, with no margin. No routine inspection or consumable costs.
We run pilots with local governments at intersections with frequent light-pollution complaints, evaluating energy savings, correct operation and legibility for drivers and pedestrians.
Downloads
If you would like to discuss our product documents, please get in touch.
Events
We present our LED traffic signals with automatic brightness control in the exhibition hall of the ITS World Congress, where ITS agencies and companies from around the world meet. Our participation is supported by the Korea Road Traffic Authority's overseas expansion program for Korean traffic safety companies.
The panel and banner shown at our booth. Click to enlarge.
Company
Light-Road Co., Ltd. began as the first in-house venture of the Korea Road Traffic Authority and was incorporated in December 2023. We research, develop and manufacture smart road traffic safety facilities, using precision light-sensing dimming technology for road safety, less light pollution and energy saving.
Contact
Call or email us and we will reply promptly.
