If you have ever looked at a tachograph printout in the summer and thought the time was an hour wrong, it probably wasn’t. Digital tachographs record in UTC, not UK local time.
What UTC is
UTC (Coordinated Universal Time) is the same as GMT, the time in the UK in winter. It does not change for daylight saving. From the last Sunday in March to the last Sunday in October, UK clocks are one hour ahead of UTC (British Summer Time), so a printout or download shows a time one hour earlier than the clock on the wall.
What gets recorded
All data on the card and in the vehicle unit, and everything printed from the tachograph, is in UTC. That is deliberate. It means a driver crossing into France, or a vehicle that changes hands, always produces records on the same time basis, and records are not distorted by clocks going forward or back.
The display
Most digital tachographs let you set a local time offset so that the clock on the display shows UK time. That is a convenience for the driver. It does not change what is recorded, which stays in UTC. If your display is set to local time and your printouts are in UTC, you will see the difference in summer. That is normal.
Why it matters in practice
- Manual entries. When a driver enters activities by hand, they must check whether the display is showing UTC or local time and enter the time on that basis. A one hour mistake can create an apparent gap, or an overlap, in the record.
- Late nights and early starts. A shift starting at 00:30 in summer is stamped 23:30 UTC the day before. If you read raw data you can think the driver worked a day earlier than they did. Good analysis software converts to local time for you.
- Daily and weekly limits. Where a day or week starts and ends can differ by an hour depending on whether you read the raw UTC record or UK local time. Make sure your analysis software tells you which it uses.
When the clock is wrong, and who can fix it
If the UTC time on a tachograph is more than 20 minutes out, GOV.UK says it must be recalibrated. That is workshop work: an approved tachograph centre must correct it, and you should keep the certificate. Drivers and operators cannot change the recorded UTC time themselves.
Quick checklist
- Know whether each vehicle’s display shows UTC or local time.
- Brief drivers on this before they enter manual records, especially after the clocks change.
- If you see a clock that has drifted well away from real time, book a calibration check.
- Use analysis software that shows times in UK time and says so, so you do not have to convert in your head.
Where OperatorSafe fits
OperatorSafe reads the UTC records and shows every time in UK time (BST or GMT), never UTC, so what you read on the screen matches the clock on the wall. See how tachograph analysis works.
If you would like a Transport Manager to review your drivers’ hours, HGV Consult can introduce an external Transport Manager.
See what OperatorSafe does
Driver checks, vehicle and driver files, maintenance planning and tachograph analysis. Unlimited drivers, from £49 a month.
More guides
- Why you need tachograph and fleet compliance software, and which features matter
- How to get a digital tachograph company card, and what it lets you do
- How to download a digital tachograph vehicle unit, step by step
- How to download a driver card, and how often you must