How does the 90-hour rule work?
The calculation always looks at two neighbouring fixed weeks. You add the driving time in the previous fixed week to the driving time in the current fixed week. The combined total must not exceed 90 hours.
The pairs overlap. That means you must check week one plus week two, then week two plus week three, then week three plus week four. The calculation does not simply reset after every second Sunday.
A simple 90-hour-rule example
If you then drove 38 hours in week two, week three would be checked against week two—not week one. Under the two-week total alone, week three could contain up to 52 hours of driving because 38 + 52 = 90. The 56-hour weekly maximum would also still apply.
How do I calculate the driving time remaining?
Two limits have to be checked together:
- Weekly allowance remaining: 56 hours minus the driving recorded in the current fixed week.
- Two-week allowance remaining: 90 hours minus the previous fixed week and current fixed week driving.
The smaller result is the useful figure. It is not unconditional permission to drive: daily driving limits, breaks, daily and weekly rest, working time and any applicable derogations must still be considered.
What counts towards the 90 hours?
The rule concerns driving time, not the whole paid shift. Other work, breaks and periods of availability do not become driving time simply because they occur during the duty. Drivers should use their tachograph record as the authoritative source for driving totals.
How do the 9-hour and 10-hour daily limits fit in?
The normal daily driving limit is nine hours. It may be extended to ten hours no more than twice in a fixed week. These daily limits apply alongside the 56-hour weekly and 90-hour two-week limits, so satisfying one total does not automatically satisfy the others.
Common questions
Does the 90-hour limit reset every fortnight?
No. It applies to every pair of consecutive fixed weeks, so the calculation overlaps from one week to the next.
Can an HGV driver drive 56 hours in both weeks?
No. Two 56-hour weeks would total 112 hours and breach the 90-hour two-week limit.
Does POA count towards the 90 hours?
No. A valid period of availability is not driving time. It is also normally excluded from working time under the sector-specific working-time rules.
Can an app replace my tachograph record?
No. A personal app can help explain and monitor recorded totals, but tachograph and employer compliance records remain authoritative.
This guide was checked against the DVSA’s Drivers’ hours and tachographs: goods vehicles — assimilated and AETR rules. Rules can change, and individual circumstances or exemptions may affect which rules apply.
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