Guides / Hours of Service basics
Hours of Service, explained in plain English
Hours of Service (HOS) rules limit how long a commercial driver may drive and work before resting. They exist because fatigue causes crashes. They are also one of the most common sources of roadside violations and audit findings, usually because a driver misunderstood a limit rather than ignored it. This guide covers the federal rules for drivers of property-carrying vehicles. Passenger-carrying drivers have different limits.
The 11-hour driving limit
After 10 consecutive hours off duty, a driver may drive up to 11 hours. Once those 11 hours are used, no more driving until another 10 consecutive hours off duty. (49 CFR 395.3(a)(3))
The 14-hour window
The 14-hour limit is a window, not a total. It starts when you begin any work after 10 hours off, and you may not drive after the 14th hour. Lunch, fuel stops and waiting at a dock all count against it. Taking time off duty in the middle does not extend it, except through the sleeper berth provision below. (49 CFR 395.3(a)(2))
The 30-minute break
You must take at least a 30-minute break after 8 cumulative hours of driving without one. The break can be off duty, in the sleeper berth or on duty not driving (fueling, for example), as long as it is 30 consecutive minutes without driving. (49 CFR 395.3(a)(3)(ii))
The 60/70-hour limit and the 34-hour restart
A driver may not drive after being on duty 60 hours in 7 consecutive days, or 70 hours in 8 consecutive days if the carrier operates every day of the week. It is a rolling total, so hours from 8 days ago drop off each day. A driver can reset that total by taking 34 or more consecutive hours off duty. (49 CFR 395.3(b) and (c))
Splitting the 10-hour break: the sleeper berth
A driver with a sleeper berth can split the required 10 hours off into two periods: one of at least 7 consecutive hours in the sleeper berth, and another of at least 2 consecutive hours off duty or in the sleeper, together totaling at least 10. When paired this way, neither period counts against the 14-hour window. The math is easy to get wrong, and errors here are a common audit finding. (49 CFR 395.1(g))
Exceptions worth knowing
- Adverse driving conditions. If unexpected conditions such as snow, fog or a closed road come up, a driver may extend the 11-hour and 14-hour limits by up to 2 hours to reach a safe place. Conditions known before the trip started do not qualify. (49 CFR 395.1(b))
- Short-haul. A driver who stays within 150 air miles of the normal work reporting location, returns to that location and is released within 14 consecutive hours, and gets the required 10 hours off between shifts, does not need logs or the 30-minute break. The carrier must instead keep time records (start time, end time and total hours each day) for six months. A driver who stays out overnight or runs past 14 hours does not qualify that day. (49 CFR 395.1(e)(1))
- Agricultural and other exemptions apply to specific operations. Check the exact conditions before relying on one.
Where drivers get caught
- Treating the 14-hour window as 14 hours of work rather than 14 hours on the clock.
- Logging a break the receipts contradict. Auditors compare logs against fuel receipts, bills of lading and toll records.
- Using personal conveyance to advance a load, which is not personal conveyance.
- Leaving logs uncertified or unidentified driving time unassigned on the ELD.
A carrier is responsible for its drivers' compliance as well as the driver. A periodic audit of logs against supporting documents is the best way to find problems before an FMCSA investigator does.