Modern vehicles remember more than most drivers assume. In the moments around a collision, the control units record a series of data points that can later be read out and used to establish how the event came about. That data does not depend on what the parties remember and it does not change under pressure.<\/p>\n
EDR is the abbreviation for Event Data Recorder, a system in the vehicle that records data relating to a collision. It is often called the black box of a vehicle, by analogy with aviation, although its function is considerably narrower.<\/p>\n
An EDR does not record continuously and does not store the history of your driving. It is triggered around an event that the system recognises as a collision or as close to one, and it retains a short record from before and after that moment.<\/p>\n
The scope of the record is not the same in every vehicle. It depends on the manufacturer, the model, the year and the equipment, so before any read out is done it is established what the particular vehicle records at all.<\/p>\n
The read out is carried out with a dedicated tool that connects to the diagnostic port of the vehicle or directly to the control unit. Working with the Bosch CDR system requires certification, and separately so for the technician who performs the read out and for the analyst who interprets the report.<\/p>\n
The raw report is not in itself an expert report. It is a set of values that have to be interpreted in the context of the particular vehicle and the particular event. Incorrect interpretation is just as dangerous as having no data at all.<\/p>\n
In disputed cases this data can clear up the questions on which the case turns:<\/p>\n
The last item matters in cases where there is suspicion that the damage did not occur in the way it was reported.<\/p>\n
It does not make sense for every claim. It makes sense when the amount is significant, when the parties disagree about how the event unfolded, when there is a serious physical injury, or when the other side claims something that does not match the traces on the vehicles.<\/p>\n
Timing matters too. The record can be overwritten by later events or lost when the power supply is disconnected or during repair or dismantling of the vehicle. If you suspect the data will be needed, ask for the read out before the repair.<\/strong><\/p>\n There are a good many misunderstandings about this system, so it is worth saying what it does not do.<\/p>\n Data from the vehicle is one source, not the only one. A reconstruction is built by cross referencing several independent sources: traces on the carriageway, deformation on the vehicles, the position of scattered parts, statements from those involved and photographic documentation from the scene.<\/p>\n When the measured data matches the physical traces, the conclusion is considerably firmer. When it does not match, that in itself raises a question that has to be explained, and often that is precisely the most valuable finding in the case.<\/p>\n Simulation tools then make it possible to present and test the event, by examining whether the proposed course of events could produce the traces and deformation found at all.<\/p>\n Access to data from a vehicle is not unlimited. As a rule the consent of the owner of the vehicle or an order from the authority conducting the proceedings is required. This is a legal question that is resolved before the technical part, not after it.<\/p>\n Reading out and interpreting data from a vehicle are part of traffic accident reconstruction<\/a>, together with reconstruction of the event using simulation tools. There is more about our qualifications and equipment on the page about our team<\/a>.<\/p>\nWhat an EDR is not<\/h2>\n
\n
How the data fits into a reconstruction<\/h2>\n
What to do if you think the data will be needed<\/h2>\n
\n
Who is allowed to access the data<\/h2>\n