The tachograph produces data; the rules about what you do with that data are where operators actually live. Between the download intervals, the record-carrying duties, the clock quirks and the manual-entry rules, tachograph data management is a system of numbered obligations - and the operators who get into trouble are almost always the ones who treated the numbers as approximate.
The core rhythm, from the official drivers’ hours and tachograph guidance: operators must periodically download data from the vehicle unit - the digital or smart tachograph itself - every 90 days, and from driver cards every 28 days, and analyse the information to ensure the rules have been complied with.
Three things in that sentence carry weight. The intervals are outer limits, not targets: download more frequently if your operation benefits, never less. The download duty sits on the operator, not the driver - a driver who never offers their card does not dilute your obligation. And downloading is only half the sentence: the data must be analysed for compliance. A server full of unread .ddd files is not compliance; it is storage. DVSA examiners ask what the analysis found, what was done about it, and where that is recorded.
The carried-record rules shift with the work. Drivers undertaking international journeys between the UK and the EU should keep full daily records for the previous 56 days. Drivers on international journeys under AETR rules to, from or through non-EU countries should keep a full set of records for the previous 28 days - enforcement agencies in other countries may have different production requirements. For domestic work the production window differs again, and the practical fleet standard is to brief drivers to carry the widest set their work might demand.
During a fixed week with no driving under the assimilated rules, drivers must as a minimum record their other work and availability activities and rest periods in blocks - including the start and end times of any weekly rest periods. A driver on a week of warehouse duties is not outside the records system; they are in a lighter-duty corner of it.
Where activities happen away from the vehicle or the tachograph cannot capture them, manual records fill the gap, and the guidance is specific about method:
The detail that decides whether a manual entry is worth anything at enforcement: the identifiers. An unattributed printout is scrap paper; the name, card number and licence number on the back are what tie it to a person and a week.
A digital or smart tachograph’s internal clock runs on UTC. The display can show local time, but all data is recorded against the UTC clock. Between the last Sunday in March and the last Sunday in October, UTC is one hour behind British Summer Time - and drivers must account for that difference when making manual entries. The 06:30 start written as 05:30 is not a typo; it is an hours discrepancy waiting for an examiner to find it. Brief it every spring and autumn, and make sure whoever reviews the data understands which clock a disputed entry belongs to.
Analogue users have their own version: the 12-hour clock face shows am and pm identically, and analogue tachographs must continue to display the correct time, including British Summer Time adjustments.
The tachograph rules are generous to the organised and merciless to the casual - every obligation is a number, and every number is checkable. Run the numbers as a system and they stop being obligations and start being evidence.