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Data elements explanation for TF meeting on 21/10/20:

Introduction on accident research

The accident research TRL performs as part of the Road Accident In-depth Studies (RAIDS) involves detailed investigations of a representative sample of road collisions. This involves attending the collision scene or inspecting the involved vehicles at a recovery yard, accessing police investigation files, hospital injury data and driver questionnaires. The purpose of these investigations is not to apportion blame for the collision to the involved parties but to determine in a systematic manner all factors (vehicle, environmental/infrastructure and human factors) that contributed. The cases are captured in an anonymous in-depth database that enables a variety of safety studies to be carried out.


Data element: Brake pedal position

Knowledge of the brake pedal position from an EDR record could enable future research for instance into the interaction between driver braking and AEBS. AEBS systems commonly provide means for the driver to interrupt a system brake intervention, which can be driver inputs on the steering wheel, accelerator or brake pedal. No detailed technical requirements are defined in regulation in this regard, but only high-level aspects which the manufacturer needs to interpret to define an override strategy (“ the interruption may be initiated by any positive action (e.g. kick-down. operating the direction indicator control) that indicates that the driver is aware of the emergency situation”; UN R152 ). Some early AEBS implementations were observed to use light brake application by the driver as a mechanism to interrupt an intervention, which could cause detrimental effects on safety as this might occur in cases where the AEBS intervention is justified but the driver’s subsequent brake response is not sufficient to substitute for it. An EDR record of the brake pedal position could for example be used for a study to investigate:

  • Whether collisions can be observed in the field where this override mechanism has exacerbated collision outcomes,
  • Therefore, whether more detailed stipulations on permissible override strategies could be added in regulation to improve safety, and
  • What minimum level of driver brake application would be a safe indication of a conscious decision by the driver to take back control.


Data element: Brake failure warning indicator status

This data element should record at least whether or not a red brake failure warning signal was provided. The red warning signal indicates failures “ within the vehicle braking equipment which preclude achievement of the prescribed service braking performance and/or which preclude the functioning of at least one of two independent service braking circuits. ” (UN R13-H)

Knowledge of the brake failure warning indicator status from an EDR record would allow to determine a brake failure as a contributory cause of a collision. This could enable future studies for example into the prevalence of collisions where a brake failure was present, indicated to the driver and the vehicle was nevertheless used on-road. If such cases were identified in the field, this would enable regulators to consider countermeasures such as adaptations to roadworthiness inspection rules or driver education.