Emergency Brake Display for Rear End Accident Avoidance Dr. J. Gail Ressort „Active Vehicle Safety, Emissions, Energy“ Bundesanstalt für Staßenwesen (Federal Highway Research Institute) Bergisch Gladbach, Germany

2 Dr. rer. nat. Jost Gail, Referat F1, Bundesanstalt für Straßenwesen Content requirements for an emergency brake display examples optimum solution criteria for activation / deactivation regulations concerned

3 Dr. rer. nat. Jost Gail, Referat F1, Bundesanstalt für Straßenwesen Requirements for an Emergency Brake Display (1) fast perception (also by distracted drivers) short reaction times easy implementation and refitting maximum deceleration of the following car intuitive display (no learning necessary) few levels

4 Dr. rer. nat. Jost Gail, Referat F1, Bundesanstalt für Straßenwesen Requirements for an Emergency Brake Display (2) threshold values corresponding to real braking behaviour functionality for emergency braking on low-µ-surfaces unambiguous display not confusing minimised effects of habituation

5 Dr. rer. nat. Jost Gail, Referat F1, Bundesanstalt für Straßenwesen Example 1: Increased Light Surface Area and Intensity 1) 2)

6 Dr. rer. nat. Jost Gail, Referat F1, Bundesanstalt für Straßenwesen Increased Area and Intensity pros: –intuitively –no learning process –causes adequate brakings of the following driver (early maximum brake force) –reduced reaction times cons: –lights have to be fixed by the driver‘s eyes –difficult refitting –vehicle design

7 Dr. rer. nat. Jost Gail, Referat F1, Bundesanstalt für Straßenwesen Example 2: Integral Brakelight 3rd upper brakelight:  too many levels G (  19 levels)

8 Dr. rer. nat. Jost Gail, Referat F1, Bundesanstalt für Straßenwesen Example 3: Flashing Brakelights (flashing)

Flashing Brakelights reduction in reaction time: (source: DaimlerChrysler)

10 Dr. rer. nat. Jost Gail, Referat F1, Bundesanstalt für Straßenwesen Flashing Brakelights pros: –good perception also by distracted drivers –reduced reaction times –easy refitting cons: –learning process might be necessary

11 Dr. rer. nat. Jost Gail, Referat F1, Bundesanstalt für Straßenwesen Example 4: Flashing Hazard Warning Lights (flashing)

Flashing Hazard Warning Lights reduction in reaction time: (source: DaimlerChrysler)

13 Flashing Hazard Warning Lights pros: –good perception –reduced reaction times –easy refitting cons: –change in colour –usual meaning: warning in case of: broken down vehicle accident end of congestion –automatical switching only if deceleration > 1.5 g

14 Dr. rer. nat. Jost Gail, Referat F1, Bundesanstalt für Straßenwesen Example 5: Continuously Shining Rear Direction-Indicators pros: – easy refitting cons: – change in colour – meaning is not intuitively clear

15 Dr. rer. nat. Jost Gail, Referat F1, Bundesanstalt für Straßenwesen Optimum Solution (1) keeping the colour coding: red light = braking flashing to achieve best perception by distracted drivers (3 Hz to 5 Hz flashing)

16 Optimum Solution (2) optional: increase in surface area of lower brakelights additional to flashing upper brakelight 1) 2) (3 Hz - 5 Hz)  best perception + intuitive display for severe braking

17 Dr. rer. nat. Jost Gail, Referat F1, Bundesanstalt für Straßenwesen Criteria for Activation / Deactivation (1) threshold deceleration 7 m / s 2 emergency brake assistance system anti-lock brake system pressure of the brake system / brake force change of vehicle velocity (real deceleration)

18 Dr. rer. nat. Jost Gail, Referat F1, Bundesanstalt für Straßenwesen Criteria for Activation / Deactivation (2) switching on immediately after detection of emergency braking switching off after –releasing the brake pedal or –after standstill of the vehicle or –detection of the end of the severe braking by a brake assistance / anti-lock braking system threshold velocity 5 km / h

19 Dr. rer. nat. Jost Gail, Referat F1, Bundesanstalt für Straßenwesen Regulations Concerned ECE-R 7, ECE-R 48 and Vienna Convention red flashing upper brakelight increase in surface area definition of activation of brakelights changing display during braking fixing of switching criteria