Definition
Hours of service (HOS) limit a driver’s driving and on-duty time in a period. They are a hard constraint on the transport plan: if routing ignores them, ETA and On Time OTIF stop being credible.
If your TMS promises 14 hours of wheel time with no rest, you do not have a plan — you have a scheduled Late.
Related: routing · driver duty day · OTIF.
What it means in practice
HOS is not only “do not drive at night”: it includes on-duty windows, rest, and accumulators that change by lane and jurisdiction.
A dock appointment that assumes an impossible HOS arrival pushes no-shows, detention, and illegal pressure on the driver.
Why it matters by role
| Role | What they must see | If they ignore HOS |
|---|---|---|
| Traffic / routing | Feasible ETA | Broken promises |
| Carrier | Compliance and fatigue | Fines / incidents |
| Shipper | Realistic appointments | Late OTIF |
| Freight procurement | Honest lead time | Impossible “cheap” rate |
What to plan with HOS
| Element | Question | Note |
|---|---|---|
| Drive limit | Max hours? | By jurisdiction |
| Rest | Where and when? | In the plan |
| Appointments | Fit with HOS? | Dock |
| Dwell buffer | Expected dwell? | Do not flood |
| Evidence | Logs / GPS? | Audit |
How to respect HOS in 5 steps
Select a step to see detail
Step detail · 01
Read constraint
Step 1
Expensive mistakes
1.Routing only by average km/h
You forget dock, meals, and sleep.
2.Selling an appointment that breaks HOS
Late is born in the plan, not on the road.
3.Pushing the driver to “make it”
Unacceptable human and legal risk.
4.Not distinguishing MX vs US rules
A cross-border lane is not one clock.
OCL and the trip file
OCL helps plan and track trips with visible ETAs and exceptions. HOS compliance belongs to the carrier/driver; OCL is not an authority or a PAC.
Sources and further reading
Key takeaways5 points
- Hours of service (HOS) = legal/operational limits on driving and on-duty time that your routing plan must respect.
- Ignoring them creates impossible ETAs, Late OTIF, and fatigue risk — not “optimization.”
- In Mexico, autotransport duty/rest rules apply; on US lanes FMCSA rules may also apply.
- Routing and booking must include rest, appointments, and dock dwell in the same plan.
- OCL helps surface realistic ETAs and exceptions; it does not replace the carrier’s legal compliance. OCL can stamp invoices and Carta Porte.
Do your ETAs respect HOS — or only the spreadsheet?
Frequently asked questions
Limits on driving and on-duty time that constrain a legal, safe routing plan.
Related: duty day describes the workday; HOS is the limit framework that day must respect.
Yes: impossible plans create detention, relays, and Late that someone pays.
Primarily the carrier/driver; shippers should not demand illegal ETAs.
Logs, GPS, and trip/dock timestamps in the trip file.
Plan vs reality visibility so you do not sell impossible appointments.