Cars have black boxes. What data do they collect?

Starting in July, all new cars sold in the EU must be equipped with an Event Data Recorder (EDR). The goal is to make it easier to investigate accidents. How do cars’ black boxes work and where can we find them?

13. 6. 2024 Škoda World

How does it work?

Cars don’t actually need to be fitted with a new physical device – the EDR is just a new software feature, and the airbag control unit and its memory are used to store the mandatory data. The data is continuously written to the memory, but the stored data are overwritten again and again with new data unless the car’s restraint systems (airbags, in simple terms) are activated.

“In the event of an accident, the system saves data in the recorder for five seconds before the impact and a maximum of five seconds after it,” Večerník explains. In that case, the data are stored permanently and cannot be edited, changed or deleted in any way. “Data can’t be force-fed into the control unit,” Jan Večerník points out.

Škoda cars can be fitted with an array of assistance systems warning of impending collisions, but one can never predict the unpredictable.

So what does the EDR store in the event of an accident? “The system primarily records data relating to the collision itself, such as restraint activation times, seat occupancy status, speed changes etc. Other information is also stored, though, such as the car’s speed before the impact, its deceleration in longitudinal and lateral directions, the state of the accelerator and brake pedal, the steering wheel angle, information on the status of ABS and ESP, and engine revs,” says Jan Večerník. In total, there are more than a thousand pieces of data and values that the various units of the car send to the airbag control unit.

Data not accessible for drivers or service centres

The collected data are only intended to help clear up traffic accidents. “Neither the car’s user nor any service technician, nor any other unauthorised person will have access to the data,” Večerník explains. “The data can only be read using a special tool with the appropriate licence. As a rule, police officers or court experts will be the only people authorised to access the data,” Jan Večerník adds.

The EDR collects information about the brake and accelerator pedal states, among other data.

The data stored in the recorder are certainly not used to monitor drivers’ behaviour. There are no obligations or consequences for the driver as a result of storing the data. At the same time, there is no risk that someone could try to change the data after an accident to put the blame on a driver who was not at fault.