47INF11.PPT
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Transcript of 47INF11.PPT
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Emergency Brake Display forRear End Accident AvoidanceDr. J. Gail
Ressort Active Vehicle Safety, Emissions, Energy
Bundesanstalt fr Staenwesen(Federal Highway Research Institute)Bergisch Gladbach, Germany
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Contentrequirements for an emergency brake displayexamplesoptimum solutioncriteria for activation / deactivationregulations concerned
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Requirements for anEmergency Brake Display (1)fast perception (also by distracted drivers)short reaction timeseasy implementation and refittingmaximum deceleration of the following carintuitive display (no learning necessary)few levels
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Requirements for anEmergency Brake Display (2)threshold values corresponding to real braking behaviourfunctionality for emergency braking on low--surfacesunambiguous displaynot confusingminimised effects of habituation
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Example 1: Increased Light Surface Area and Intensity
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Increased Area and Intensitypros:intuitivelyno learning processcauses adequate brakings of the following driver (early maximum brake force)reduced reaction timescons:lights have to be fixed by the drivers eyesdifficult refittingvehicle design
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Example 2: Integral Brakelight3rd upper brakelight: too many levelsG( 19 levels)
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Example 3: Flashing Brakelights
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Flashing Brakelights reduction in reaction time: (source: DaimlerChrysler)
Diagramm1
1.51.32
21.73
with distraction
without distraction
Effective Reaction Time / s
Effective Reaction Times with and without Distraction
Tabelle1
with distractionwithout distractionwith distractionwithout distraction
1.51.321.51.32
usual brakelights + flashing hazard warning lights1.751.5usual brakelights21.73
usual brakelights21.73
Tabelle1
with distraction
without distraction
Effective Reaction Time / s
Effective Reaction Times with and without Distraction
Tabelle2
with distraction
without distraction
Effective Reaction Time / s
Effective Reaction Times with and without Distraction
Tabelle3
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Flashing Brakelightspros:good perception also by distracted driversreduced reaction timeseasy refittingcons:learning process might be necessary
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Example 4: Flashing Hazard Warning Lights
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Flashing Hazard Warning Lightsreduction in reaction time: (source: DaimlerChrysler)
Diagramm2
1.51.32
1.751.5
21.73
with distraction
without distraction
Effective Reaction Time / s
Effective Reaction Times with and without Distraction
Tabelle1
with distractionwithout distractionwith distractionwithout distraction
1.51.321.51.32
usual brakelights + flashing hazard warning lights1.751.5usual brakelights21.73
usual brakelights21.73
Tabelle1
with distraction
without distraction
Effective Reaction Time / s
Effective Reaction Times with and without Distraction
Tabelle2
with distraction
without distraction
Effective Reaction Time / s
Effective Reaction Times with and without Distraction
Tabelle3
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Flashing Hazard Warning Lightspros:good perceptionreduced reaction timeseasy refittingcons:change in colourusual meaning: warning in case of:broken down vehicleaccidentend of congestionautomatical switching only if deceleration > 1.5 g
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Example 5: Continuously Shining Rear Direction-Indicators pros: easy refitting cons: change in colour meaning is not intuitively clear
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Optimum Solution (1)keeping the colour coding: red light = brakingflashing to achieve best perception by distracted drivers
(3 Hz to 5 Hz flashing)
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Optimum Solution (2)optional: increase in surface area of lower brakelights additional to flashing upper brakelight1)2)(3 Hz - 5 Hz) best perception + intuitive display for severe braking
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Criteria for Activation / Deactivation (1)threshold deceleration 7 m / s2emergency brake assistance systemanti-lock brake systempressure of the brake system / brake forcechange of vehicle velocity (real deceleration)
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Criteria for Activation / Deactivation (2)switching on immediately after detection of emergency brakingswitching off afterreleasing the brake pedal orafter standstill of the vehicle ordetection of the end of the severe braking by a brake assistance / anti-lock braking systemthreshold velocity 5 km / h
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Regulations ConcernedECE-R 7, ECE-R 48 and Vienna Conventionred flashing upper brakelightincrease in surface areadefinition of activation of brakelightschanging display during brakingfixing of switching criteria