What is a Type 4 Street Light?

A Type 4 street light—also known as a 4th‑generation intelligent LED street light—is a modern roadway luminaire that uses fourth‑generation LED chips as its light source. These fixtures deliver high luminous efficacy, low power consumption, long service life, and reliable performance while minimizing light pollution. Equipped with smart sensing and ICT integration, Type 4 street lights adapt their output in real time to traffic and environmental conditions, offering enhanced safety, energy savings and operational efficiency.

Key Features

• Fourth‑Generation LED: Uses the latest high‑efficiency LED chips for superior lumen output and uniformity.
• Energy Efficiency: Consumes significantly less power—up to 40% savings—compared to traditional lamps.
• Long Lifespan: Rated for tens of thousands of operating hours with minimal lumen depreciation.
• Smart Control: Integrates microcontrollers, PLC or ZigBee networks, and various sensors for dynamic management.
• Applications: Suitable for main roads, secondary streets, industrial parks, urban‐rural connectors and campus pathways.

Principle of Operation & Applications

1. Real‐Time Fault Reporting

Traditional street‐light fault detection relies on manual patrols, leading to delays and high maintenance costs. Type 4 lights use Power‑Line Communication (PLC) to report status and failures instantaneously to the central management system, enabling rapid response and reducing manpower.

2. Adaptive Illuminance Control

Embedded light sensors and microwave human/vehicle detectors continuously monitor ambient brightness and traffic flow. Through ZigBee or PLC links, the system automatically adjusts lumen output:

• Low‐traffic periods: dim to a safe low level.
• Peak hours or when pedestrians/vehicles are detected: switch to high lumen output for optimal visibility.

Experimental trials in Toulouse, France show up to 50% energy reduction by doubling brightness only when movement is detected, then returning to dimmed mode after 10 seconds of no activity.

3. Dynamic Color‐Temperature Adjustment

By adding sensors for fog, ambient light or emergency conditions, Type 4 street lights can shift their color temperature—mimicking vehicle fog lamps or enhancing contrast—to improve visibility in challenging weather or incident response scenarios.

Future Prospects

In many cities, pedestrian and vehicular flow drops sharply after late evening. Yet conventional fixtures stay at maximum output until dawn, wasting energy. Type 4 lights promise true “smart energy” by matching illumination strictly to demand—avoiding ad‐hoc lamps‑off schemes that compromise safety. With public lighting accounting for over 30% of municipal electricity use (≈439 billion kWh/year in China alone), wide adoption of intelligent LED systems could cut costs by hundreds of millions annually while improving urban security.

Technical Principle

A built‑in microcontroller modulates the LED drive current via high‑frequency (kHz‑range) PWM. For instance, a 50% duty‐cycle (0.5 ms on, 0.5 ms off) yields half brightness without perceptible flicker. Programmable schedules and sensor‐driven triggers allow customized brightness profiles based on city zone, time, and traffic density—all executed automatically in each lamp.

Advantages Over Traditional Luminaires

• Directional Efficiency: LEDs emit light directionally, unlike omnidirectional gas lamps that lose much output in reflectors.
• Rapid Response: Instant on/off and dimming versus slow‐ramping sodium or mercury lamps.
• Reduced Maintenance: Lower failure rates and remote diagnostics minimize service calls.
• Environmental Impact: No hazardous materials, lower carbon footprint, and reduced light pollution.

As LED technology continues to advance, smart, adaptive street lighting will become the new global standard—delivering safer roads, cleaner cities and sustainable energy use for decades to come.