Glossary
Hours of Service (HOS)
Federal rules limiting how many hours a commercial driver can drive and work before a mandatory rest period. ELDs automatically log HOS compliance instead of relying on a paper logbook.
What Hours of Service means in practice
Hours of service (HOS) are the rules that limit how long a commercial driver can drive and work before a mandatory rest period, and they are the reason the ELD mandate exists. The numbers differ by country. A US property-carrying driver can drive 11 hours inside a 14-hour on-duty window after 10 consecutive hours off, with a 30-minute break after 8 hours of driving. Under Canada's federal rules, a driver can drive up to 13 hours and be on duty up to 14 in a day, with at least 10 hours off.
The 14-hour window is the limit people misread most. In the US it runs on the wall clock and does not pause for breaks, fuel or loading, so a long wait at a dock eats directly into available driving time.
For dispatch, the practical value is seeing hours remaining before assigning a load, not finding out after a driver is committed to a run they cannot legally finish. A cross-border ELD has to apply the US or Canadian ruleset for where the driving happens, and drivers should know their remaining hours can shift at the border.
Read the full explainer
The definition above is the short version. The page below explains Hours of Service (HOS) in depth, with the rules, numbers and examples behind it.
What Is an ELD?Guides that explain Hours of Service (HOS)
- FMCSA ELD Exemptions: Does Your Fleet Need One?
- DVIR Meaning: What Is a Driver Vehicle Inspection Report?
- Route Optimization Software: What It Does and When It Pays
- AOBRD vs ELD: What Changed in the Transition and Why It Matters
- Trucking Dispatch Software for Freight: What to Look For
- Integrated vs. Designated ELD: What's the Difference?
- How Much Does an ELD Cost? What Drives the Price
- Canada's ELD Mandate: Dates and How It Differs From the US
Hours of Service: common questions
Are hours-of-service rules the same in Canada and the US?
No. The US allows 11 hours of driving inside a 14-hour on-duty window, with a 30-minute break after 8 hours of driving. Canada's federal rules allow up to 13 hours of driving and 14 hours on duty in a day. Weekly cycles differ too, so a cross-border ELD must switch to the ruleset for where the driving happens.
Does the 14-hour window stop when I take a break?
No. Under US rules, the 14-hour on-duty window runs continuously once it starts and does not pause for breaks, meals, fuel stops or loading. Only the 11 hours of driving are limited inside it. That is why long detention at a shipper or receiver cuts directly into the driving time a driver has left that day.
What is the difference between Cycle 1 and Cycle 2 in Canada?
Cycle 1 caps on-duty time at 70 hours over 7 days and resets with 36 consecutive hours off. Cycle 2 caps it at 120 hours over 14 days, resets with 72 consecutive hours off, and requires 24 consecutive hours off before driving past 70 accumulated on-duty hours. The ELD tracks the counters automatically.