# fleet.drivers-hours

Status: needs review by a drivers' hours / transport compliance expert before it is published.

Checks a driver's recorded activities against the driving-time and break
rules of Regulation (EC) No 561/2006, as it applies in Great Britain
(assimilated law, formerly "retained EU law"). It returns every breach it
finds, in time order, with the local date and time the limit was passed.

```
checkDriversHours("2026-09-21", "06:00", [
  { kind: "driving", minutes: 300 }, { kind: "rest", minutes: 45 }
])
// { compliant: false, drivingMinutes: 300,
//   breaches: [{ rule: "break", at: "2026-09-21T10:30", actual: 300, limit: 270 }] }
```

## Input

The activities are back to back from `startDate` and `startTime`: each one
starts when the previous one ends, as on a tachograph printout. `kind` is
`driving`, `work` (other work), `availability` (a period of availability) or
`rest` (any break or rest). Neighbouring activities of the same kind are
merged, so a rest recorded as 20 minutes then 25 minutes is one uninterrupted
45-minute break.

Times are local wall-clock time with no time zone or clock change handling.

## Rules checked

| rule | limit | meaning |
|------|-------|---------|
| `break` | 270 minutes | Art. 7: more than 4h30 of driving without a qualifying break. `actual` is the driving in that driving period, up to the break that ended it |
| `daily-driving` | 600 minutes | Art. 6(1): daily driving time over 10 hours |
| `daily-driving` | 540 minutes | Art. 6(1): a third (or later) day over 9 hours in one fixed week; `at` is when that day passed 9 hours |
| `weekly-driving` | 3360 minutes | Art. 6(2): over 56 hours in one fixed week |
| `fortnightly-driving` | 5400 minutes | Art. 6(3): over 90 hours in two consecutive fixed weeks; `at` falls in the second week |

How the activities are read:

- **A break** is a rest of at least 45 minutes, or a rest of at least 15
  minutes followed later by one of at least 30 (in that order: 30 then 15 does
  not count). Other work and periods of availability are not breaks. A
  15-minute rest before any driving in the period is not the first part of a
  split break, since it is not taken during the driving period.
- **A daily rest** is a rest of 9 hours or more. It ends the daily driving
  time (Art. 4(k)); a shorter rest, including the 3-hour first part of a split
  daily rest, does not.
- **Weeks** are fixed weeks, 00:00 Monday to 24:00 Sunday (Art. 4(i)).
  Driving that crosses Sunday midnight counts in both weeks, minute by minute.
  A day's 10-hour extension counts in the week its first driving falls in.
- **The end of the records** closes the last driving period and day, so
  records that stop mid-day are judged on what they show.

Whether daily and weekly *rest* was taken is a separate check:
`fleet.tachograph-rest`.

## What it does not do

- GB domestic drivers' hours rules (Transport Act 1968), AETR, or mixed
  domestic/EU days.
- Multi-manning, ferry or train crossings (Art. 9), the Art. 12 emergency
  departure, and the exemptions and national derogations (Art. 3 and 13).
- The working-time limits (Road Transport (Working Time) Regulations 2005),
  including the 6-hour work break rule.
- Weeks outside the records: the fortnightly check only adds up weeks it has
  data for, so pass the previous week's activities too if they matter.

## Data

The limits are dated rows in `data/limits.json`, effective from 11 April 2007
(Art. 29) and still in force. A date before that is an error.

## Sources

- Regulation (EC) No 561/2006, as it applies in the UK, legislation.gov.uk:
  Article 4 (definitions of break, rest, daily rest, week, daily driving time,
  driving period), Article 6 (9h/10h twice a week, 56h, 90h), Article 7
  (45 minutes after 4h30; 15 then 30), Article 29 (entry into force 11 April
  2007). https://www.legislation.gov.uk/eur/2006/561/contents
- DVSA, "Drivers' hours: Assimilated rules":
  https://www.gov.uk/drivers-hours/eu-rules
- DVSA, "Drivers' hours and tachographs: goods vehicles", section 1 (split
  break order 15 then 30, other work and availability are not breaks, fixed
  week): https://www.gov.uk/guidance/drivers-hours-goods-vehicles/1-eu-and-aetr-rules-on-drivers-hours

1.0.1 fixes Python accepting a trailing newline or non-ASCII digits in startDate and startTime; adds tests.

## Before you rely on this

**Not professional advice.** This capability calculates drivers’ hours figures from published rules. It is a software component for developers, not legal advice. Rules change and every rate here has an effective date. Check that the dates cover your case. Verify results against the official sources listed above, and have a transport compliance specialist (DVSA rules) review how you use it, before anyone relies on the output. Provided "as is" under its licence, without warranty.

**Unreviewed.** This capability's implementations agree in every language and pass its published test vectors, which were worked out from the official sources cited. But no qualified transport compliance specialist (DVSA rules) has yet checked those vectors, or confirmed that the capability covers the cases it claims. Treat it as a draft. Do not use it for real people, money or decisions without your own expert review. Once a qualified reviewer signs off, this notice is replaced with their name, qualification and the date. Each new version needs fresh sign-off.

## Notices

Contains public sector information licensed under the Open Government
Licence v3.0 (https://www.nationalarchives.gov.uk/doc/open-government-licence/version/3/).

Legislation: Crown copyright and database right.

1.0.2 marks it unreviewed and adds its attribution notices (NOTICE). The code and the tests are unchanged.