tachograf

A tachograph is a device installed in commercial motor vehicles to record driving time, speed and other events related to vehicle operation. Its purpose is to verify compliance with drivers' working hours, mandatory rest breaks and to support road safety and enforcement. There are two main generations: analog tachographs, which record data on a rotating chart using a stylus, and digital tachographs, which store data in an onboard unit and use driver, operator and workshop cards for access.

Analog tachographs produce a physical chart that shows driving time, breaks and rest periods. Digital tachographs log driving time, rest periods, breaks and related events in securely stored electronic records. The driver card authenticates the driver, the operator card is used by fleet managers to access data, and the workshop card is used by approved service centers to calibrate, download and verify data. Data protection and tamper-resistance are provided by dedicated memory, encryption and digital signatures.

Regulatory framework and usage vary by region but have common features. In the European Union, tachographs are mandatory for most vehicles over 3.5 tonnes gross vehicle weight and for passenger vehicles with at least nine seats. Digital tachographs became standard in EU regulation during the 2000s, with ongoing requirements for data storage, access and enforcement. Authorities can download and review tachograph data to verify compliance with driving time, rest and break rules. Outside the EU, many countries operate tachograph-like systems under their own regulations, sometimes with different card and data-handling procedures.

Limitations include dependence on proper usage, card handling and device maintenance; data reflect recorded events and may not capture every movement or exception. Despite controls, enforcement relies on regular inspections and cross-checks with other records.