The rules in one line (property-carrying drivers): after 10 hours off, a driver may drive up to 11 hours, only within a 14-hour window, with a 30-minute break after 8 hours of driving, and no more than 60 hours in 7 days or 70 hours in 8 days on duty, reset by 34 hours off.
Why dispatchers must know HOS
Hours of service (HOS) decide which loads a driver can legally take. Book a load the driver can't reach in time without breaking the rules and you have three bad options: a late delivery, a driver pressured into a violation, or a cancelled load. The rules are in 49 CFR Part 395; FMCSA's plain-language summary is the best quick reference.
The four limits
| Rule | What it means |
|---|---|
| 11-hour driving limit | Up to 11 hours of driving after 10 consecutive hours off duty. |
| 14-hour window | Driving is only allowed within 14 consecutive hours after coming on duty. Breaks, waiting and loading do not pause this clock. |
| 30-minute break | Required after 8 cumulative hours of driving. It can be off duty, sleeper berth or on duty not driving (for example, waiting at a dock). |
| 60/70-hour limit | No driving after 60 hours on duty in 7 days, or 70 hours in 8 days (depending on the carrier's schedule). A 34-hour off-duty period restarts the count. |
The 14-hour window is the one that catches people
Drivers rarely run out of the 11 driving hours first. They run out of the 14-hour window, because waiting at shippers and receivers burns it. Two hours of detention at pickup is two hours of the window gone, even though the truck didn't move. This is why dispatchers push for appointment times, document detention, and avoid stacking a long wait in front of a long drive.
Worked example
A driver comes on duty at 6:00 after a 10-hour break.
- 6:00–7:00: pre-trip inspection and drive to the shipper (on duty, 0.5 h driving).
- 7:00–10:00: waiting and loading (on duty, not driving).
- 10:00–17:30: driving, 7.5 hours (8 hours driving total).
- 17:30–18:00: the required 30-minute break.
- 18:00–20:00: driving, 2 more hours (10 hours driving total).
The 14-hour window closes at 20:00 (6:00 + 14). Even though the driver has 1 driving hour left on the 11-hour limit, they must stop at 20:00. A delivery that needs 11 hours of driving that day was never possible once the shipper held the truck for three hours.
Sleeper-berth split
Drivers with a sleeper berth can split the 10-hour off-duty period into two parts: one of at least 7 hours in the sleeper berth and one of at least 2 hours (off duty or sleeper), adding up to at least 10 (for example 7/3 or 8/2). When paired correctly, neither period counts against the 14-hour window. Splits are useful for working around appointment times, but the arithmetic is easy to get wrong; the FMCSA summary has diagrams.
Exceptions dispatchers meet most
- Adverse driving conditions: unexpected weather or traffic can extend the 11-hour and 14-hour limits by up to 2 hours.
- Short-haul exception: drivers who stay within a 150 air-mile radius and return to their work reporting location within 14 hours can be exempt from ELDs and the 30-minute break. Common in local work and drayage.
- Personal conveyance: moving the truck for personal reasons while off duty, under limits. Not a way to stretch hours for a load.
ELDs: the hours are recorded automatically
Most interstate drivers must use an electronic logging device that records driving time from the engine (49 CFR 395 Subpart B). For dispatchers this means two things: you can see the driver's remaining hours in the carrier's ELD portal, and "fixing the logs" later isn't an option. Plan with the real numbers.
Dispatcher rules of thumb
- Before booking, ask: how many hours does the driver have left today, and on the 60/70?
- Count waiting time at the dock as burned window time.
- Plan the restart: a driver near 70 hours needs 34 hours off before a long run.
- Never ask a driver to run over hours. It's illegal, unsafe and puts the carrier's safety record at risk.
FMCSA runs pilot programs and proposes changes to HOS from time to time. Always check the current FMCSA summary before relying on a detail.
Sources
- 49 CFR Part 395, hours of service of drivers
- FMCSA, Summary of Hours of Service Regulations