Forensic Analysis of Digital Tachograph Data
Since May 2006 all new vehicles registered in the EU have been required by law to be fitted with a digital tachograph device. The tachograph is used to record drivers activity and in the old analogue tachograph, speed, distance travelled and mode of work were recorded on a circular wax covered paper chart. Drivers of vehicles fitted with a digital tachograph are supplied by the DVLA with a drivers card, upon which their hours of work/driving is stored on a chip within their card. No speed data is stored on the drivers card. The details on the drivers card, speed data and hours worked is also stored on internal memory within the tachograph unit. Speed data has to be stored in all instruments in 1Hz format, however some instruments also store speed data in a 4Hz format. Speed data in 1Hz format is only stored for 24 hours total driving time before it is overwritten, whereas 4Hz data is transient and is only stored on a cycle of 3 hard decelerations of stop events before it is overwritten. The speed data can only be downloaded from the instrument with a Control Card which are issued to the Police and VOSA
When a Police Collision Investigator attends collisions which involve a vehicle fitted with a digital tachograph they will routinely download the vehicles speed data using their Control Card. If this has been done, this data will be held by the Police or VOSA and will not routinely be available. We offer advice to our clients with regard to how approaches can be made to secure such data and are able to offer the analysis of recovered speed data from digital tachographs in both 1 Hz and 4 Hz format.
Collision Forensics Ltd use Digital Analyst Software supplied by AiTS to perform the analysis and will provide a report detailing the findings. We are able analyse this data, produce it in report format and link it to other evidence in the reconstruction of collisions.