Glossary
Hours of Service (HOS)
Plain-language HOS meaning, key federal limits, and why hours shape parking, fuel, and appointment decisions before the truck moves.
By Dale Connors, Founding Editor · Content reviewed quarterly against FMCSA guidance and official state resources. Definition
Hours of Service (HOS) rules are federal regulations that limit and structure commercial truck driver duty time and driving time. The rules establish maximum daily driving hours, a total duty window, required break periods, and a cumulative weekly on-duty limit.
HOS rules apply to commercial motor vehicle drivers operating in interstate commerce. The specific rules depend on the operation type (property-carrying, passenger, short-haul, etc.), the ELD configuration, and carrier policy. Always verify current rules with FMCSA guidance, the ELD, and your carrier.
Key HOS limits for property-carrying drivers
| Limit | Simple description | Planning implication |
|---|---|---|
| 11-hour driving limit | Maximum driving time after a qualifying off-duty period | Use as a ceiling, not a daily planning target |
| 14-hour duty window | Total window from first on-duty to required stop | Runs continuously — non-driving activities consume it |
| 30-minute break | Required after 8 hours of cumulative driving | Placement affects the rest of the day |
| 60/70-hour weekly limit | Rolling cumulative on-duty hours (7 or 8 days) | Track mid-week; plan restart before it becomes an emergency |
| 34-hour restart | Resets the weekly cumulative limit after 34 off-duty hours | Location and services matter for the next load |
Why it matters in trip planning
HOS rules shape when a truck can move, stop, break, and recover time. Trip plans fail when the clock is treated as paperwork after the fact.
The most important planning insight is that the 14-hour duty window runs continuously from the moment the driver goes on duty — through loading, waiting, fueling, breaks, and traffic. Every non-driving activity that occurs while on duty consumes the window, which is why dispatch plans that only account for driving time regularly produce end-of-day parking emergencies.
What to check before relying on this
Verify current FMCSA guidance, the ELD display, operation type, and carrier policy before making compliance decisions. HOS rules have changed over time and contain exceptions and exemptions that depend on the specific operation.
Related terms
- 11 hour rule
- 14 hour clock
- 30 minute break
- 34 hour restart
- ELD
What's the most common dispatch planning mistake involving HOS?
Treating the 11-hour driving limit as the day's endpoint without accounting for on-duty non-driving time. A plan that estimates 9 hours of driving at 55 mph doesn't account for the shipper check-in, the 30-minute break, the fuel stop, traffic through one metro, and the parking search at the far end. None of those activities count against the 11-hour driving limit — but they all run the 14-hour window. A dispatcher who builds a plan around driving hours alone is handing a driver a trip that works only if nothing takes any on-duty time that isn't driving.
What's the practical difference between the 60-hour and 70-hour weekly limits?
The 60-hour limit applies to drivers on a 7-consecutive-day cycle; the 70-hour limit applies to those on an 8-day cycle. Most OTR operations use the 8-day/70-hour cycle for the additional weekly capacity. The difference shows up mid-week: a driver on the 8-day cycle has a larger bank to draw from during heavy weeks, but used hours drop off the rolling window more slowly — so a driver who runs hard Monday through Wednesday stays compressed for longer than someone on the 7-day cycle would.
Are HOS rules the same for all commercial trucking operations?
No. The standard federal property-carrier rules apply to most OTR interstate operations, but exceptions exist for short-haul, agricultural, oilfield, and certain intrastate operations. The short-haul exemption alone can eliminate the ELD requirement and modify break requirements for qualifying operations — a significant practical difference for regional carriers. Any operation that isn't straightforwardly OTR interstate should verify which rule set applies rather than assuming the standard federal limits govern.