Move the calculation point, then count again
Calculate the hours left after a valid pair.
How to recalculate
First check that both rests qualify. Then calculate from the end of the first rest, excluding the qualifying paired rests. Subtract driving from eleven and counted window time from fourteen. Also check the work and driving around the pair. Cycle hours and the driving-break rule still apply.
A worked timeline shows which activity stays in the new calculation.
Work through a 7/3 pair
Assume the driver starts after full qualifying rest and has enough cycle hours.
| Time | Activity | Duration |
|---|---|---|
| 6–7 a.m. | On-duty work | 1 hour |
| 7–11 a.m. | Driving | 4 hours |
| 11 a.m.–2 p.m. | Off-duty rest | 3 hours |
| 2–7 p.m. | Driving | 5 hours |
| 7 p.m.–2 a.m. | Sleeper berth | 7 hours |
Count from the end of the first rest
At 2 a.m., the pair is complete. The new calculation starts at 2 p.m. Five driving hours count, leaving six of eleven. Five window hours count, leaving nine of fourteen. The seven-hour berth is excluded.
Think of moving the start mark on a ruler. It is not a blank ruler: the driving and work after that mark still count.
The same method works for 8/2
Instead, rest 11 a.m.–1 p.m., drive 1–6 p.m., then use the sleeper 6 p.m.–2 a.m. At 2 a.m., calculate from 1 p.m. Five driving and five window hours count. Six driving hours and nine window hours remain, subject to other limits.
Chaining requires another valid calculation
A rest period can be used in successive qualifying pairs. Each pair and its surrounding driving must meet the limits. Hours shown in anticipation of a future rest depend on actually completing that rest.
A split does not restore exhausted cycle hours.