Twenty years ago a road traffic claim turned on two statements, a sketch and a repair estimate. Today the same collision may be recorded three or four times over: by the vehicle’s own event data recorder, by driver-assistance systems that intervened or did not, by a dashcam, and by a telematics box installed for insurance. The evidence is better than it has ever been. It is also widely misunderstood.
What the vehicle records
Event data recorders. New vehicles are required to carry an event data recorder under UN Regulation 160. It captures a short window around a collision: vehicle speed, brake application, accelerator position, steering input, seat-belt status, airbag deployment and the change in velocity experienced during the impact. It is objective, time-stamped and difficult to argue with, provided it is downloaded properly and interpreted by someone who understands what each parameter means.
Advanced emergency braking. Under UN Regulation 152, automatic emergency braking systems detect an imminent collision and brake if the driver does not. The system’s logs can show whether a warning was issued, when braking began and how hard. That bears directly on reaction time and on whether a driver could have avoided the impact. It also raises a new question: if the system did not intervene, was that because the situation was outside its design limits, or because something was wrong with it?
Other assistance systems. Lane-keeping, adaptive cruise control and blind -spot monitoring all leave traces. Whether the vehicle was under adaptive cruise control at the moment of impact, for example, changes the analysis of following distance and reaction entirely.
What the camera records
Dashcam footage is now routine in claims. It is persuasive, which is exactly why it needs care.
- Frame rate and compression limit how precisely speed and timing can be measured from video. A plausible-looking estimate from footage can be wrong by a margin that matters.
- Lens distortion and field of view alter perceived distance and closing speed, particularly at the edges of the frame.
- Audio and timestamps are not always reliable, and metadata can be absent or edited.
- The camera sees one perspective. It cannot show what the other driver could see.
Properly analysed, with reference points measured on the ground, footage can yield robust speed and timing evidence. Casually viewed, it mostly confirms what the viewer already believed.
What the telematics box records
Insurance telematics sample position, speed and acceleration at intervals. The data is useful for showing how a vehicle was being driven in the minutes before a collision, and for corroborating or contradicting a statement. It is usually too coarse to reconstruct the impact itself, and the sampling rate should be stated before any conclusion is drawn from it.
Getting the data, and keeping it lawful
Vehicle data is personal data. Obtaining it requires the owner’s consent or a proper legal basis, and in litigation it falls within disclosure. Event data is often overwritten if the vehicle is driven on or repaired; preserving it early is one of the most valuable steps a party can take. Footage from third -party cameras raises its own data protection questions.
Using it to settle
The practical point is this: when the data is good, there is very little left to argue about. A mediation or joint settlement meeting at which the event data, the braking logs and the footage have been analysed and exchanged in advance is a very different event from one built on competing witness statements. The parties can see what happened. What remains is the negotiation about consequences, and that is what a settlement day is for.
A mediator who can read the data, and explain in plain terms what it does and does not prove, helps both sides move from positions to numbers faster. That is the job, and it is becoming a technical one.