Test Strategies for Adaptive Beam Headlights
Don't Be Blinded When It Comes to Assessing New Technology
01 December 2020
Traditionally, headlamps have formed a compromisebetween illuminating the road and blinding other drivers with oncoming glare from your vehicle. This is due to their composition of an upper beam – which provides good forward illumination but is uncomfortably bright for oncoming drivers – and a lower beam, limited in forward illumination while remaining at a comfortable level. A combination of improvements and new technology has led to adaptive beam headlamps, capable of intelligently illuminating the road while avoiding glare for other drivers by incorporating improved optical performance and LED lighting systems with automation technology based on image recognition sensors.
Adaptive driving beam (ADB) systems vary the location and intensity of projected light by using a grid to illuminate different portions of the road and automatically dim/switch portions of the headlight off to reduce intensity as needed. The beams remove the compromise between glare and illumination and the need for the operator to manually switch between upper and lower beams. The result is improved response time, and safety for both the driver and oncoming vehicles.
While this technology emerges and evolves, the industry must adapt their testing for headlamps to accommodate the changes. SAE J3069 provides a set of testing and performance requirements for these products, combining recommendations from experts from manufacturers, suppliers, test labs, and regulatory bodies. It includes all tests normally required for a traditional static headlamp, as well as a dynamic test designed specifically for adaptive driving beams. This includes:
- Dynamic testing: Includes test drives at a set of stimulus vehicle fixtures and at least a 155-meter test section over which a test vehicle maintains constant speed at or above the ADB activation threshold. It also uses lux measurements at representative locations to establish glare limits for the ADB system
- Stimulus fixtures: Comprised of oncoming and preceding vehicles and motorcycles. Each fixture includes representative white or red stimulus lights with intensity and specifications to maximize test repeatability, as well as glare sensor locations typical for a driver's eye or mirror locations.
- Test drive: Glare limits are set at specific test distances from 155 meters to 30 meters between the ADB vehicle and the glare sensors. The test track must be flat and straight through at least this portion of the test drive. The standard requires minimal extraneous ambient light (from reflective or other natural or manmade sources) within the immediate field of view of the glare sensors or ADB vehicle.
- Data acquisition: Illuminance data must be collected for each glare position at a minimum rate of 10Hz. Additionally, the distance between the vehicles equipped with adaptive beam headlamps and illuminance meters must be accurate to 2 meters and 6 percent.
- Sudden appearance variants: The vehicle must respond to a motorcycle stimulus fixture that suddenly appears at 155 meters. This is meant to simulate a sudden appearance due to cresting a hill, rounding a corner, entering the roadway, etc.
While SAE J3069 provides the foundation for assessing adaptive beams, additional guidance has been issued by the US National Highway Traffic Safety Administration (NHTSA), United Nations, and the Federal Motor Vehicle Safety Standards (FMVSS), and to date there is still not a final rule regarding requirements for adaptive beam technology for use on US roads. Learn more about the requirements and how Intertek assesses adaptive beams by downloading our webinar recording.
Learn more about our Adaptive Beam Headlight Testing solutions.
Senior Project Engineer
Nathan Danks is a Senior Projects Engineer in the Intertek Photometrics group and specializes in automotive lighting testing. He began dynamic testing of adaptive forward lighting systems in 2018 and is involved in the SAE lighting committee. His background also includes EMC and Radiological Protection testing, and he has a bachelor's degree in Physics from Calvin College.