ADAPTIVE DRIVING BEAM (ADB) TESTING AND TEST PROCEDURE DEVELOPMENT Elizabeth Mazzae, National Highway Traffic Safety Administration, Vehicle Safety Research

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Purpose: • Test existing ADB systems and develop objective test procedure

Research questions: • Does ADB work as advertised? • Can ADB meet existing lower beam requirements?

Work steps: • Test European-spec ADB-equipped vehicles as per ECE’s R48 and R123

vehicle-based type approval test procedures • Based on ECE TP and lessons learned from step 1, develop an objective,

repeatable test procedure for ADB • Perform objective, vehicle-level test procedure; evaluate ADB performance

and test repeatability

Project Scope

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What is ADB?

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ADB – Type of adaptive front lighting system that adapts its beam pattern to the presence of oncoming and preceding vehicles

Improves long-range visibility for the driver through increased upper beam illumination of the roadway

• Avoids glaring other road users by shading other vehicles

• Designed to activate at speeds above typical city driving speeds – Activation at 19-43 mph

• Permitted as optional equipment in Europe, Japan

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How does ADB work?

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ADB system uses existing headlamp • Adds:

– Sensor (camera & image processing unit) – ECU – Control on column stalk – Instrument panel telltale (see photo upper right)

Adaptation accomplished in one of two ways: • Mechanical shade blocks part of the headlight beam • Multi-light source systems turn off individual bulbs (e.g., Audi Matrix Beam)

Audi ADB with preceding & oncoming vehicles

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Determined how to run ECE driving scenarios on closed courses • Fully crossed ECE TP road types and traffic scenarios with

geometries & numbers of lanes to get matrix of scenarios • Drop scenarios that may be unsafe to perform (e.g., overtaking on

winding road) • Determined how to run ECE driving scenarios on closed courses

Investigated objective performance measures: • Glare Illuminance (lux) from ADB

Investigated objective performance criteria: • Glare Illuminance limits derived from FMVSS No. 108

Changed perspective of tester: • ECE evaluator drives ADB-equipped vehicle • Investigated use of instrumented “other vehicle” to measure the glare

coming from the ADB-equipped vehicle

ADB Testing: ECE R48 TP Implementation

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ECE

US

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ADB Testing: ECE R48 TP Implementation

• Ran pilot tests (called “Phase 1 testing”) consisting of first attempt at implementing ECE scenarios on test courses

• After Phase 1, modified the TP dynamic scenario trials set – Eliminated redundant scenarios

• Hill & slope are similar to straight, level scenario – Reduced # of scenarios in which ADB does not activate

• Illuminated roadway & multi-vehicle (traffic) scenarios – Categorized trials by road geometry rather than road type – Replaced ECE bicycle scenario with motorcycle

• FMVSS No. 108 has no bicycle requirements • Motorcycles more likely to be encountered on roadways >25 mph

– Selected appropriate test courses and scripted vehicle starting points, paths, and speeds for each scenario

• Further investigate ADB performance − ADB adaptation time trial − ADB camera (sensor) obstruction test

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Test Procedure Dynamic Maneuver Scenarios

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• Gray, italic text notes deletions in upper table; Green text notes additions in lower table

• Also measured ambient illumination and baseline lower and upper beam headlight levels

– Baseline output of DAS vehicle headlighting system lower beam mode measured in ambient lighting conditions subtracted from all trials’ illuminance measurements.

Multi-Lane Country Urban

ECE (Phase 1)

Traffic Conditions

Straight level >600 m; Curves

left, right

2-4 lanes, hills and/or slopes , dips,

intersections, and winding roads

Sections with and without

illuminationOncoming (single, multiple) x x xPreceding (single, multiple) x x xPassing (active, passive) x xOncoming Bicycle x

Modified (Phase 2) Vehicle Approaches Straight Curve (L, R)

Dip series (straight) Winding

Oncoming (180 deg. heading ∆) x, motorcycle x x xPreceding (same direction, 0 deg.) x, motorcycle x xPassing (0 deg., active, passive) x xIntersection (60, 90, 120 deg.) x

Road Trajectory

Road Types

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Data Collection Equipment

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Glare illuminance measurement points

• Used “DAS” (Data Acquisition System) vehicles to create driving scenarios & record objective data – Provided other-vehicle headlight stimulus – Housed meter, sensors, computer – 2 DAS vehicle sizes:

• “Small” (2011 Ford Fiesta) • “SUV” (2010 Acura MDX)

• Konica Minolta T-10A illuminance meter • Headlamp voltage recorded • RT Range systems in DAS and ADB vehicles

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Additional Stimulus Vehicle & ADB Test Vehicles

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ADB systems of European-spec 2014 MY vehicles were tested: – Audi A8 – BMW X5 M50d – Lexus LS460 F Sport – Mercedes Benz E350

2012 Can Am Spyder RS motorcycle

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Analysis Objectives

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Range (m) Oncoming Preceding15.0 – 29.9 3.109 18.85430.0 – 59.9 1.776 18.85460.0 – 119.9 0.634 4.041

120.0 – 239.9 0.281 4.041

Illuminance (lux)108-based lower beam glare limits

Evaluate ADB performance: 1) Does ADB adapt quickly to mitigate glare? 2) Does ADB respond appropriately when camera (sensor) is

obstructed? 3) Measured illuminance, comparison to:

• Lower beam illuminance for same vehicle

– Glare level at other vehicle location should not exceed that of lower beam

• 108-based lower beam glare limits

– Derived from FMVSS No. 108 static beam patterns (Flannigan and Sullivan, 2011; UMTRI)

4) Is ADB response to individual test scenarios repeatable?

Evaluate test procedure: 1) Does maneuver scenario elicit ADB response? 2) Are test maneuvers repeatable? (using lower beam trials)

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Preliminary Results: ADB Adaptation Time

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Measures how quickly ADB adapts to suddenly appearing DAS vehicle headlights

– ADB vehicle traveling at 62 mph, DAS vehicle 0 mph – DAS headlights switched on at 120 m range

• Left plot shows that illuminance magnitude similar to upper beam until DAS headlights are detected, then it adapts

• Adaptation time values ranged from 0.50 s - 1.92 s

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Preliminary Results: Dynamic Maneuver Results Summary

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# of ADB-equipped Vehicles per Scenario that Met 108-Derived Glare Limits (based on avg. max illuminance)

Stimulus:Small DAS

SUV DAS

Small DAS

SUV DAS

Small DAS

SUV DAS

DAS: Small SUV Small SUV Small SUV Small SUV Number of Trials Per Vehicle: 4 2 4 2 4 2 4 2

Oncoming (180 deg. heading ∆) 2/4 1/2 2/4 1/2 0/4 0/2 0/4 0/2Same lane 2/4 1/2 0/4 0/2 2/4 0/2 4/4 4/4

Adjacent lane, Left 4/4 2/2 4/4 2/2 4/4 4/4

Adjacent lane, Right 3/4 1/2 4/4 0/2 4/4 4/4

ADB passes DAS 2/4 1/2 4/4 2/2 3/4 2/2

DAS passes ADB 4/4 2/2 4/4 2/2 4/4 2/2

60 degrees 0/4 0/290 degrees 0/4 0/2120 degrees 0/4 0/2

Dip Dip series 0/4* 0/4*N T i l i h DAS i d i bi d i hi bl

Passing (same direction)

Intersection

Curve Left Curve Right

Motorcycle

Road Trajectory

Straight

Preceding (same direction)

Green = 3-4 of 4 vehicles met derived glare limits Black = Some vehicles met derived glare limits Red = No vehicles met derived glare limits

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Preliminary Results: Oncoming, Straight Small/SUV DAS vehicle; Both 62 mph

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• Lower beam data show good maneuver repeatability • ADB plots show 3 of 4 systems met derived glare limits;

BMW ADB with Small DAS vehicle was close to meeting limits (lower beam also did not meet derived limits; headlights were European-spec)

ADB Lower Beam 1 1

2 3

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Preliminary Results: Oncoming Right Curve Scenario; Both 62 mph

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• Good maneuver scenario repeatability shown in lower beam plots • Adaptation visible in ADB plots; performance variable in some cases • Curve speed may not have allowed sufficient time for ADB to respond

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Preliminary Results: Passing, Straight Scenario

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• Scenario repeatability is good overall • DAS vehicle passed ADB-equipped vehicle going same direction • All ADB systems met preceding glare limits (18.9 lux for 15-60 m range)

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Preliminary Results: Intersection 120⁰ Scenario (Oncoming; DAS vehicle stationary)

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• Repeatability for lower beam trials was very good • All ADB systems exceeded glare limits beyond range of 30 m

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Other Observations

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Other Observations • Lexus ADB consistently exhibited a brief upper beam illumination at

close range in straight oncoming scenario • Lexus ADB in one public road drive mistook reflective road signs for

oncoming vehicle and switched to lower beam • BMW ADB at times turned on upper beams momentarily between

test trials

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Summary – ADB Performance

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Answers to ADB performance research questions were all “generally, yes”:

1) Does ADB adapt quickly to mitigate glare? 2) Does ADB respond appropriately to camera (sensor) obstruction? 3) Is ADB response to individual test scenarios repeatable?

ADB illuminance exceeded derived lower beam limits in these scenarios:

1) Intersections 2) Oncoming curves (impacted by time available for ADB to

respond) 3) Preceding motorcycle (possibly impacted by location of

illuminance sensors, not directly on motorcycle) – For all other scenarios, at least 2 of 4 vehicles met UMTRI-derived

glare limits

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Summary – Test Procedure

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ECE test procedures employ a set of traffic scenarios and focus on observing the light ADB systems provide the driver of an ADB-equipped vehicle

NHTSA research effort replicated ECE test procedure scenarios but used FMVSS No. 108-like perspective of measuring how much light headlights cast on other vehicle drivers

Research applied objective, repeatable measures to those test procedures

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For more information:

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• See NHTSA technical report “Adaptive Driving Beam

Headlighting System Glare Assessment,” DOT HS 812 174, August 2015

• elizabeth.mazzae@dot.gov