Guide
DOT Hours-of-Service Compliance Basics
Two clocks run at once under 49 CFR 395: the 11-hour driving limit and the 14-hour on-duty window. This guide covers both, the 30-minute break rule, the 60/70-hour weekly limits, sleeper berth splits, common violations, and how to read what the HOS calculator is actually telling you.
The three daily limits, and the one that actually stops you
Property-carrying drivers work against three federal limits at once, all in 49 CFR 395.3. Only the first three rows below are things a driver actively watches during a shift — the rest are weekly totals covered further down.
| Limit | Value | Starts / resets on |
|---|---|---|
| Driving limit | 11 hr | 10 consecutive hours off duty |
| On-duty window | 14 hr | Coming on duty; runs continuously and does not pause for breaks, fuel, or loading |
| Break requirement | 30 min | Required after 8 cumulative hours of driving time |
| Off-duty requirement | 10 hr | Consecutive, before the next 11-hour/14-hour cycle can begin |
The 14-hour window is a clock, not a budget. It runs from the moment you come on duty and keeps running through breaks, fuel stops, and dock time — none of that earns time back. Only 10 consecutive hours off duty resets it. Whichever limit — the 11-hour driving cap or the 14-hour window — runs out first is the one that actually stops you on a given day, and it changes depending on how the day went.
The 30-minute break rule, precisely
This is the rule drivers most often misremember, and the 2020 revision to Part 395 changed it in two ways that matter: it is triggered by driving time, not on-duty time, and it no longer requires going off duty.
| Question | Answer |
|---|---|
| What triggers it? | 8 cumulative hours of driving time since the last qualifying interruption |
| How long? | At least 30 consecutive minutes |
| What counts? | Any 30 consecutive minutes not driving — off duty, sleeper berth, or on duty not driving |
| Does it pause the 14-hour window? | No. The window keeps running through it |
| What happens if you skip it? | Driving is prohibited under 395.3(a)(3)(ii) until it is taken — not a recommendation, a violation |
Because on-duty-not-driving time now qualifies, a pre-trip inspection, a dock wait, or fuelling can satisfy the break — provided it is 30 consecutive minutes and it is logged that way. Stacking several short stops does not count; the 30 minutes has to run together.
Sleeper berth splits: pairing periods instead of one 10-hour block
395.1(g) lets a driver split the required 10 hours off duty into two periods using the sleeper berth, instead of taking it all at once. Since the 2020 revision, the split can be 7/3 or 8/2 (previously only 8/2 was allowed), and — this is the part worth understanding — neither qualifying period counts against the 14-hour window, which is what makes the split useful rather than just a scheduling curiosity.
- The pairing. One period of at least 7 consecutive hours in the sleeper berth, paired with a second period of at least 2 consecutive hours, either in the sleeper berth or off duty. The two periods together must total at least 10 hours.
- Neither period, by itself, satisfies the 10-hour off-duty requirement. It is the pair, taken together, that does.
- The 14-hour window calculation excludes the qualifying sleeper berth period. That is the entire point of the provision — it lets a team or long-haul driver work around a single unbroken 10-hour block without it costing daily driving time.
- Only sleeper berth time — never off-duty time alone — can be the 7-hour half of the pair. The shorter, second period may be off duty or sleeper berth.
The 60-hour/7-day and 70-hour/8-day limits, and the 34-hour restart
The 11-hour and 14-hour rules govern one shift. A separate, rolling weekly limit governs the whole week, and it is the one this site's HOS calculator does not model — see "How to use the HOS calculator correctly" below.
| Rule | Limit | Applies to |
|---|---|---|
| Weekly on-duty limit | 60 hr / 7 days | Carriers that do not operate every day of the week |
| Weekly on-duty limit | 70 hr / 8 days | Carriers that operate every day of the week |
| 34-hour restart | 34 hr consecutive off duty | Optional; resets the 60/70-hour total back to zero |
The 60/70-hour total is a rolling window, not a hard weekly reset — as the oldest day ages out of the 7- or 8-day period, its hours drop off the total automatically, whether or not you take a restart. The 34-hour restart is an optional shortcut for getting back to zero sooner; nothing requires using it, and a driver can run indefinitely on the rolling window alone as long as the oldest hours keep aging out faster than new ones accrue.
Worked example
On duty at 06:00, the clock now reading 15:00, 6.5 hours driven, 30-minute break already taken:
- Elapsed on duty = 15:00 − 06:00 = 9.00 hr
- 14-hour window left = 14 − 9.00 = 5.00 hr
- 11-hour driving left = 11 − 6.50 = 4.50 hr
- The smaller of the two governs = 4.50 hr, on the 11-hour limit
Change one thing — 8.5 hours driven, with the break not taken — and the answer becomes 0.00 hr, binding on the 30-minute break under 395.3(a)(3)(ii). The 14-hour window still shows 5.00 hours and the driving limit still shows 2.50, but neither is available: past 8 cumulative hours of driving without a qualifying interruption, driving is not legally permitted at all until the break is taken — which is exactly the case the HOS calculator's break warning exists to catch.
Where drivers actually get put out of service
- Missing the 30-minute break. The single most common HOS violation in roadside inspection data — often from a driver who tracked the 11 and 14 correctly and simply lost count of cumulative driving time.
- Treating the 14-hour window as pausable. It is not. A two-hour dock wait is two hours gone from the window even though zero of it was spent driving.
- Running out of weekly hours with daily hours to spare. The 11-hour and 14-hour clocks can both show time remaining while the 60/70-hour total is already at zero — the day's numbers looking fine does not mean the week's numbers are.
- Misusing personal conveyance. Personal conveyance is off-duty movement unladen and not for the carrier's benefit; using the status to keep a load moving while off the clock is a falsification finding, not a grey area.
- Assuming an ELD malfunction stops the clock. It does not — a malfunctioning ELD requires reverting to paper logs for the current 24-hour period and the previous 7 days, not a pause in the rules themselves.
- Forgetting the sleeper berth pairing has to add to 10 hours. A 6-hour sleeper period paired with a 2-hour off-duty period is 8 hours, not a qualifying split.
How to use the HOS calculator correctly
PitStopCalc's Hours of Service calculator models exactly three things: the 11-hour driving limit, the 14-hour on-duty window, and the 30-minute break as a yes/no checkbox. That is stated plainly on the page itself, and it matters here because it is also everything the calculator cannot see — it has no idea what your 60/70-hour rolling total is, whether you are mid-way through a sleeper berth split, or what your last 34-hour restart looked like. Use it to get a fast answer for today's shift, then check that answer against your ELD before you rely on it, because the ELD — and only the ELD — has your actual duty-status history.
Where these rules come from
Hours of service is enforced federal law, not guidance, and every figure above traces back to one part of the Code of Federal Regulations.
- 49 CFR Part 395 — Hours of Service of Drivers — The regulation in full: the 11-hour driving limit, the 14-hour window, the 30-minute break, the 60/70-hour limits, sleeper berth provisions, and every exception to them.
- 49 CFR Part 392 — Driving of Commercial Motor Vehicles — Includes the ill-or-fatigued-driver rule, which overrides any hours left on paper.
- 49 CFR Part 396 — Inspection, Repair and Maintenance — Where on-duty-not-driving time for pre-trip inspections and repairs comes from.
Does the 30-minute break have to be off duty?
No — since the 2020 revision, any 30 consecutive minutes not driving qualifies, including on-duty-not-driving time such as a dock wait or a pre-trip inspection. It does not have to be logged as off duty or sleeper berth.
What actually happens if I violate an HOS limit?
You are placed out of service until you have accumulated enough off-duty time to come back into compliance — the vehicle cannot be dispatched further. The violation is also recorded and can affect the carrier's and driver's safety scores under FMCSA's CSA program.
Do the 60-hour and 70-hour limits reset automatically?
The total is a rolling 7- or 8-day window, so hours drop off as the oldest day ages out — there is no fixed weekly reset. A 34-hour consecutive off-duty period is an optional restart that zeroes the total sooner, but nothing requires taking one.
Are short-haul drivers exempt from hours of service?
Not from the limits themselves. The short-haul exception in 395.1(e)(1) relieves a driver operating within 150 air-miles of their work-reporting location, within a 14-hour duty period, from keeping a full record of duty status — the 11-hour and 14-hour limits still apply.
Does bad weather give me extra hours?
Adverse driving conditions under 395.1(b)(1) can extend both the driving limit and the 14-hour window by up to 2 hours, for conditions that were not known or apparent when the trip began — such as unexpected snow or a highway closure. It is not automatic and it does not apply to conditions the driver could have anticipated.