What is a Digital Tachograph?

What is a Digital Tachograph?

A digital tachograph is a physical device that records a vehicle’s speed and driver actions over time. It is usually fitted to lorries, buses, trucks and larger commercial or public vehicles. This ensures the vehicle driver and the transport operator are complying with U.K. and E.U.transport rules and laws.

A tachograph unit is usually fitted behind the speedometer or gearbox of a vehicle’s dashboard. Historically tachographs recorded driving data on a disk by analogue means. But increasingly Digital Tachographs are now the norm. They are more efficient, more accurate and more secure. They use electronic data storage and telecommunication channels (like smart phones or the WiFi) to record and transfer driver data to a central point where it is analysed and archived.

According to WikiPedia, the digital tachograph succeeded the analogue tachograph as a result of European Union regulation 1360/2002. This regulation made digital tachographs mandatory for all relevant vehicles manufactured after August 1, 2005.


Digital Tachograph System

A digital tachograph system consists of a sender unit mounted to the vehicle gearbox, the tachograph head and a digital driver card unit. The sender unit produces electronic pulses as the gearbox output shaft turns. These pulses are interpreted as speed data by the tacho’ head.

The sender unit and head are electronically paired and the pulses from the sender to the head are encrypted as a security measure / deterrent to tampering and then recorded on a driver smart-card.

Drivers are legally required to accurately record their driving activities, retain these records and produce them on demand to transport authorities (or police) who are charged with enforcing regulations that govern drivers’ working hours (WTD).

The main European Regulation (EC) 561/2006 of the European Parliament and of the Council [3] defines drivers hours.

As well as automatically receiving speed data, the tachograph records the driver’s activity selected from a choice of modes. When the vehicle is in motion, the drive mode is activated automatically. There are different modes, work mode, rest mode. The rest and availability modes can be manually selected by the driver whilst stationary.

Model Units and Card Systems

Digital Tachograph units, systems, card readers are available from various manufacturers in the UK: such as: Stonebridge, Continental and Actia SmartTach.

Each driver needs a Driver Smartcard which are used by drivers to digitally record driving information. The Operator will also have a Company Card to retrieve tachograph data from their drivers tachograph head. This card also allows a company to lock information so that it cannot be subsequently obtained by another operator.

A third type of card is a Master Control Card as used by law enforcement agencies/police to retrieve data from the tachograph head. A control card overrides any company locks put in place by operators.

And a fourth card is the Workshop Card as used by authorised tachograph technicians/engineers to fit and calibrate tachographs.