How often does a tachograph need calibrating (3 figures)

Every row is a verbatim sentence read from the named source's own page through our fetch service on the date shown, hash-pinned to the stored read (the sha of the page's visible text; the raw page is mirrored to R2).

3 of the 10 named sources that could be read published a usable figure; 7 published none and are recorded as not published, never filled in; 1 could not be read (blocked, dead or unreachable) and count nowhere.

The headline figures (median, minimum, maximum, quartiles) are over ONE figure per source in day (a source's median where its page yielded several accepted sentences), so N counts sources, never sentences; 31 candidate sentence(s) were refused by a reviewer with the reason recorded.

The fuller derivation this dataset is chartered to grow into (not yet what the figures above are; they are each source's own published figure as read): one row per duty per vehicle class per regime - the interval (digital 2-yearly test, analogue 2-yearly inspection and 6-yearly recalibration), the retrofit deadline by date of first registration, the regulation number behind it, and whether it bites on domestic or international work only - for GB, Northern Ireland and the EU side by side.

The derivation is the ANSWER A DATE PRODUCES: given a vehicle's registration date, tachograph generation and route, which deadline has already passed and which is next; and the changed-since as each amending instrument lands.

31 candidate sentences on these pages were refused by a reviewer; each refusal and its reason is recorded in the review ledger.