Adaptive Beam Headlight Testing
The United States has received a very welcome update to the FMVSS 108 headlight standard – the official allowance of adaptive beam headlights for US autos.
Adaptive beam headlights, or A.D.B. headlights (adaptive driving beam), have been allowed in virtually every country in the world up to this point, and they offer major benefits to drivers. Basically, the system allows the driver to use the full “high beam” setting at all times and a computer, controlled by sensors, adjusts the lighting to meet the conditions.
Adaptive driving beams will automatically lower their brightness when oncoming traffic is detected, allow for additional lighting to show pedestrians, bicyclists or wildlife on the edges of the road, and even adjust for climatic conditions such as rain, fog and snow. The adaptive beams effectively 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.
Adapting Test Strategies for Adaptive Beam Headlights
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The final rule, approved in February 2022, considered industry and individual comments made regarding the NPRM from October 2018 into a set of laboratory and dynamic test requirements. Much of the final rule was based on the test procedures included in SAE J3069 – the Society of Automotive Engineers recommended practice for Adaptive Driving beams -which was first published in June 2016. The new testing requirements for adaptive driving beams include all the traditional physical and photometric tests for headlamps, as well as specific logic requirements for when / where the beam must meet the low beam photometric requirements the upper beam photometric requirements, and when it can be in a transition zone. In addition, the NHTSA final rule adds a full system level dynamic test in order to prove that the ADB system will not result in excessive glare to oncoming drivers. The new dynamic test includes:
- Dynamic testing: Includes a complete matrix of test drive scenarios including multiple driving speeds and turn radii at a set of stimulus vehicle fixtures all of which include a 220-meter test section over which a test vehicle must maintain a constant speed.
- During each test drive lux measurements are made 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 headlights or tail lights 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 220 meters to 15 meters between the ADB vehicle and the glare sensors. The test track must be flat and the vehicles path must not deviate by more than +/- 0.5 m from the specified path.
- The standard requires minimal extraneous ambient light (from reflective or other natural or man-made 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 100Hz, and passed through a low-pass filter at 35 Hz. Additionally the photometers must be cosine corrected (to within 3%) and allow a maximum incidence angle of 25-degrees.
Intertek can assist OEMs and headlamp suppliers get their adaptive beam products into the US market with our extensive photometrics testing capabilities and proving grounds access. Contact us today for more information on how our Total Quality Assurance expertise can bring your A.D.B. headlamps to the roadways.