Emergency Brake Display for Rear End Accident Avoidance

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

Content • requirements for an emergency brake display • examples • optimum solution • criteria for activation / deactivation • regulations concerned 2 Dr. rer. nat. Jost Gail, Referat F 1, Bundesanstalt für Straßenwesen

Requirements for an Emergency Brake Display (1) • • • 3 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 Dr. rer. nat. Jost Gail, Referat F 1, 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 4 Dr. rer. nat. Jost Gail, Referat F 1, Bundesanstalt für Straßenwesen

Example 1: Increased Light Surface Area and Intensity 1) 2) 5 Dr. rer. nat. Jost Gail, Referat F 1, 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 6 Dr. rer. nat. Jost Gail, Referat F 1, Bundesanstalt für Straßenwesen

Example 2: Integral Brakelight 3 rd upper brakelight: G ( 19 levels) too many levels 7 Dr. rer. nat. Jost Gail, Referat F 1, Bundesanstalt für Straßenwesen

Example 3: Flashing Brakelights (flashing) 8 Dr. rer. nat. Jost Gail, Referat F 1, Bundesanstalt für Straßenwesen

Flashing Brakelights reduction in reaction time: (source: Daimler. Chrysler) 9 Dr. rer. nat. Jost Gail, Referat F 1, Bundesanstalt für Straßenwesen

Flashing Brakelights • pros: – good perception also by distracted drivers – reduced reaction times – easy refitting • cons: – learning process might be necessary 10 Dr. rer. nat. Jost Gail, Referat F 1, Bundesanstalt für Straßenwesen

Example 4: Flashing Hazard Warning Lights (flashing) 11 Dr. rer. nat. Jost Gail, Referat F 1, Bundesanstalt für Straßenwesen

Flashing Hazard Warning Lights reduction in reaction time: (source: Daimler. Chrysler) 12 Dr. rer. nat. Jost Gail, Referat F 1, Bundesanstalt für Straßenwesen

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 13

Example 5: Continuously Shining Rear Direction-Indicators • pros: – easy refitting • cons: – change in colour – meaning is not intuitively clear 14 Dr. rer. nat. Jost Gail, Referat F 1, 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) 15 Dr. rer. nat. Jost Gail, Referat F 1, Bundesanstalt für Straßenwesen

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

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) 17 Dr. rer. nat. Jost Gail, Referat F 1, 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 18 Dr. rer. nat. Jost Gail, Referat F 1, 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 19 Dr. rer. nat. Jost Gail, Referat F 1, Bundesanstalt für Straßenwesen