Tachograph Rules Made Easy: A Plain-English Guide for UK Operators

Tachograph rules sound complicated. Once you've stripped away the jargon, the framework is actually fairly simple: every commercial HGV records what the driver does, the operator keeps a copy of the data, and DVSA checks the data both at the roadside and at the operator's premises.

This guide covers tachograph rules in plain English — what tachographs do, who needs them, what counts as compliance, and where small operators most often go wrong.

General guidance, not legal advice. Tachograph rules vary by vehicle category, journey type, and operating conditions; specific exemptions apply. Always check the rules that apply to your operation against current DVSA guidance.

What a Tachograph Actually Does

A tachograph is a recording device fitted to the vehicle. It captures:

• The vehicle's speed
• The distance travelled
• The driver's activity — driving, other work, available, or rest
• Time stamps for every change in activity
• Driver identification (via a smart card the driver inserts)

Modern tachographs are digital — the data is stored electronically on the vehicle unit and on the driver's card. The few remaining analogue tachographs use paper charts, but new vehicle registrations have required digital units since 2006, and smart tachographs (a newer digital generation) since June 2019.

The point of all this recording: to enforce the rules on driving hours and rest periods that we cover in our HGV driving hours guide. Without a recording device, those rules would be unenforceable. With one, every minute of driver activity has a verifiable trail.

Which Vehicles Need a Tachograph

Most goods vehicles over 3.5 tonnes maximum authorised mass (MAM) used commercially in Great Britain need a tachograph fitted and active. The DVSA tachographs overview sets out the framework.

Some narrow exemptions exist:

• Vehicles used by the armed forces, police, fire, or civil defence
• Vehicles for non-commercial carriage of goods for personal use
• Vehicles up to 7.5t MAM carrying materials/equipment used by the driver in their work, within 100km of base
• Specialist vehicles like breakdown recovery trucks (under specific conditions)

If you're running standard haulage, courier work, skip hire, or waste collection over 3.5t, you're in scope. Don't rely on exemptions without checking the wording carefully — DVSA interprets them strictly, and a wrongly-claimed exemption is treated as a missing tachograph at roadside.

The full set of vehicle requirements is also covered in our tachograph requirements guide.

The Two Sides of Tachograph Compliance

There are two separate but related compliance obligations:

1. The Tachograph Equipment Itself

The hardware must be:

• Installed in any in-scope vehicle
• Calibrated at an approved tachograph centre — typically every 2 years for digital tachographs
• Sealed to prevent tampering — the calibration plaque shows the date of last calibration and the seals visible on the head must be intact
• Functioning — a tachograph that's broken or running on the wrong time isn't compliant; defects must be reported and repaired

A roadside check finding that the calibration is out of date, the seals are broken, or the unit is malfunctioning is treated seriously. Every offence pushes your traffic OCRS score towards amber or red, triggering more inspections.

2. The Data the Tachograph Produces

The data must be:

• Downloaded on schedule — driver cards every 28 days, vehicle units every 90 days (full procedure in our tachograph downloads guide)
• Stored for at least one year in a form that can be read and copied
• Analysed for infringements — downloading isn't enough; the operator must check the data for breaches and act on them
• Producible for DVSA on request, both at roadside and at operator premises

Failing on the data side is what catches most small operators. The hardware is usually fine. The downloads are the cliff-edge.

What "Tacho Rules" Looks Like Day-to-Day

For a sole trader running 2-3 vehicles, a working tachograph compliance routine looks like this:

Per shift:

• Driver inserts their card into the tachograph at the start of duty
• Tachograph records all activity automatically through the day
• Driver makes manual entries when changing vehicles, going off duty, or breaks
• Driver removes the card at the end of duty

Every 28 days (per driver):

• Download the driver card data using a USB downloader and company card
• Save the .ddd file to your storage system
• Run analysis to check for infringements — late breaks, insufficient rest, exceeding limits

Every 90 days (per vehicle):

• Download the vehicle unit data
• Save and analyse alongside the driver card data

Every 2 years (per vehicle):

• Book the vehicle into an approved tachograph centre for calibration
• Keep the calibration certificate for 2 years afterwards

Ongoing:

• Address infringements when they appear — re-train the driver, change scheduling, document corrective action
• Retain all data for at least 12 months

If any one of these falls down, it shows up in the data. DVSA can see exactly when the last download was and exactly which infringements went uncorrected.

Common Mistakes That Cost Small Operators

The 6 most frequent tachograph findings at operator visits, ordered roughly by frequency:

1. Missing the 28-day driver card download deadline — usually because the driver was off-shift or away
2. Manual entry gaps — drivers forgetting to log activity when swapping vehicles or going off duty
3. Letting calibrations lapse — easy to overlook because the next due date is 2 years away
4. Storing only the analysis report, not the raw download — DVSA wants the original .ddd file
5. Treating tachograph data as something to file and forget — never running infringement analysis means breaches go uncorrected
6. Wrong company card — using a card belonging to a different licence-holder during a download invalidates the audit trail

Each of these adds traffic points to your OCRS score. Multiple findings at one visit can trigger a Traffic Commissioner referral.

When You Need a Tachograph Analysis System

For 1-2 vehicles and a single driver, manual analysis of .ddd files using a free reader is workable but tedious. By 3-4 vehicles or 2+ drivers, the volume of data makes manual analysis unreliable — it's easy to miss a 30-minute infringement when there are 30 days of mixed activity to scan.

That's where dedicated analysis software comes in. The decision points: how often you'll be analysing data, whether you need automated infringement flagging, and how the data integrates with your wider compliance records. For sole-trader operators below 10 vehicles, a lightweight analysis tool that handles .ddd parsing + WTD checks + an audit trail is usually enough — anything heavier is overkill until your fleet grows.

Sources

• Tachographs overview — GOV.UK
• Types of tachograph — GOV.UK
• Tachograph data and downloads — GOV.UK
• Drivers' hours — GOV.UK
• Operator Compliance Risk Score — GOV.UK