Driving Hours API: Measure Driving and Rest Times to the Minute
Driving Hours API: measure driving and rest time to the minute and catch the 4.5-hour wall before dispatch
One overrun day can strand a trailer, trigger a roadside fine and turn a profitable lane into a loss. Most fleets still discover driving-time problems at month end, when the tachograph download finally reaches the office. This guide shows how a driver API turns Regulation (EC) 561/2006 from a retroactive paperwork duty into a constraint the route planner respects before the truck leaves the yard.
Why are driving and rest hours a routing problem, not a payroll problem?
Because time behind the wheel decides which route is physically possible. A plan that reads 5 h 10 min on the map fails the moment the driver hits the 4.5-hour mark 60 km short of the unloading gate. Checking hours afterwards means the dispatcher is always reacting: re-planning at the barrier, paying a night on a service area, or asking the driver to break the law.
Remaining driving time belongs in the planner as a hard constraint, exactly the way axle count belongs in toll costing. The system should answer "can this driver legally reach the ramp?" before it answers "which road is cheapest?". One calculation, two questions.
What limits must the system know from Regulation (EC) 561/2006?
The regulation sets the arithmetic. These values must be stored per driver and per card, not as a fleet average — 2026 reference, and national derogations still need checking before each international run:
| Rule | Limit under Reg. (EC) 561/2006 | What the API checks before departure |
|---|---|---|
| Continuous driving | 4 h 30 min | Remaining block until the mandatory break |
| Mandatory break | 45 min, splittable as 15 + 30 min | A realistic break location on the planned corridor |
| Daily rest | 11 h, or 9 h reduced max 3 times between weekly rests | Rest start time before the arrival window closes |
| Weekly driving | 56 h in any single week | Card balance for the current week |
| Two-week driving | 90 h across two consecutive weeks | Rolling total across the driver's cards |
| Weekly rest | 45 h, or 24 h reduced with compensation | Whether the tour can finish inside the week |
Fed with the driver's live card state, these lines replace "should be fine" with "arrives with 38 minutes of driving left".
How does an API measure working time in real time?
The second-generation smart tachograph (G2V2) writes driving, other work, availability and rest onto the driver card and into the vehicle unit, tamper-evidently. What changes the operation is the structured export: the API reads card and vehicle files directly instead of an office clerk retyping printouts.
Every record is mapped to a driver, a vehicle and a tour, and the balances update as the card is read. The measured position therefore matches what an inspector sees on the card — the API mirrors the legal record, it never replaces it. A 40-truck fleet typically recovers the equivalent of one clerical role, and the data arrives in minutes rather than in a weekly batch.
Worked example. A driver starts a Monday shift with 3 h 35 min of the block already used. The planner has 55 minutes of legal driving before the break, then a fresh 4 h 30 min block. A 480 km run predicted at 6 h 40 min of driving is flagged as not completable in one shift; the system proposes a break window at km 210 and a reduced daily rest at destination, so the customer's 08:00 slot still holds.
What does "rest-aware routing" actually mean?
It means the route ends at the latest moment the driver can legally arrive and begin rest — not at the cheapest kilometre. Before departure the API compares remaining driving time against planned driving time including live traffic and weather, so a route that looks short but sits in a two-hour queue is scored honestly.
When a delay appears mid-tour, a what-if simulation answers the only question that matters: does 40 extra minutes push the arrival past the point where daily rest can still start? The countermeasures it ranks are practical:
- Pull the break forward to a parking area 25 km earlier.
- Hand the last leg to a second driver inside the 90-hour envelope.
- Move the delivery to the next morning and pre-book a secure park.
How do the driver app and the dispatcher stay aligned?
The driver app shows remaining driving time, the next recommended break window and the nearest legal rest area with parking capacity. The dispatcher console shows the same numbers from the same source — no more two screens with two answers.
That alignment is commercial, not cosmetic: a dispatcher who cannot see the remaining block either under-uses the truck or pushes an illegal instruction.
How do you connect tachograph and working-time data to TMS and ERP?
Through an open API. Driver, card and working-time records flow into your transport management and ERP system, where driving hours become cost-centre entries, overtime becomes payroll lines, and rest becomes capacity that sales can see before committing a lane.
Synchronisation runs both ways: assignments from the TMS define the tour, tachograph records report actual working time back. The end-to-end flow is described under how it works.
What is the shortest path from card read-out to a legal plan?
- Link every driver to a card and a vehicle, so no record floats unattributed.
- Read the card before dispatch and compute the remaining block, not the hours already used.
- Put break and rest windows into the route as constraints, never as corrections.
- Re-run traffic, weather and delay live; trigger a what-if when arrival risk exceeds 20 minutes.
- Push measured times to TMS and ERP, and keep an audit trail for inspections.
FAQ
Does the API replace the driver's duty to comply with driving times? No. Compliance stays a shared legal responsibility of driver and operator. The software measures, warns and plans so decisions are taken early and on evidence.
How accurate is the pre-departure check? Exact on card data, and as accurate as traffic prediction on the road. Uncertainty is returned as a band — 6 h 20 min to 6 h 55 min, for instance — instead of a single false-precision number.
What happens if a driver uses two cards or a hired vehicle? Records are keyed to driver identity, so totals aggregate across cards and vehicles. Gaps and overlaps are flagged for review instead of quietly inflating available capacity.
Can reduced daily rest be planned automatically? Yes, up to three times between two weekly rests. The planner counts usage per driver and refuses a fourth reduced rest inside the same interval.
Measure the hours you actually have
Driving and rest time becomes plannable once it is measured, checked before the wheels turn and built into the route. TRANSCEND reads tachograph data, recomputes remaining driving time in real time and tells you before dispatch whether a run is legal — then prices it with tolls, fuel and delivery windows. Book a live demo or see the plans.