Hours-of-Service (HOS): Rules Every Truck Driver Must Know
Hours-of-Service (HOS) regulations are among the most strictly enforced FMCSA rules for commercial truck drivers. These regulations limit how long drivers may operate a commercial motor vehicle (CMV) and require specific rest periods to reduce fatigue-related accidents.
Introduction
HOS regulations are governed by 49 CFR Part 395. Compliance is mandatory for most commercial drivers who operate CMVs in interstate commerce. Failure to adhere to these limits results in violations that impact both driver safety scores and carrier compliance profiles.
The Four Core HOS Limits
To maintain compliance, every driver must manage four primary time-based thresholds:
1. The 11-Hour Driving Limit
A driver may drive a maximum of 11 hours after 10 consecutive hours off duty. Once the 11-hour driving limit is reached, the driver must be off duty for another 10 consecutive hours before driving again.
2. The 14-Hour On-Duty Limit
The 14-hour duty window is a “daily” limit. A driver may not drive beyond the 14th consecutive hour after coming on duty, following 10 consecutive hours off duty. Importantly, the clock does not stop for lunch breaks or short rest periods.
3. The 30-Minute Rest Break
Drivers must take a 30-minute break after 8 cumulative hours of driving time (without at least a 30-minute interruption). This break can be taken as off-duty, sleeper berth, or on-duty (not driving) status.
4. The 60/70-Hour Weekly Limit
Drivers may not drive after being on duty for 60 hours in any 7 consecutive days or 70 hours in any 8 consecutive days. This limit resets only after a driver takes 34 or more consecutive hours off duty.
Why These Rules Matter
The primary goal of HOS is to combat driver fatigue. According to FMCSA research, fatigued drivers have slower reaction times and reduced situational awareness. From a business perspective:
- Audit Risk: HOS logs are the first thing reviewed during a DOT audit.
- Financial Risk: Fines for HOS violations can reach thousands of dollars.
- Operational Risk: Serious violations lead to immediate Out-of-Service (OOS) orders.
How these rules lead to OOS orders is detailed in our Hours-of-Service Violations Guide.
Compliance Controls
Managing HOS requires a structured approach:
- Real-Time Monitoring: Use your ELD to track remaining drive time—don’t rely on memory.
- Trip Planning: Schedule stops and fuel breaks ahead of time to account for the 14-hour window.
- Log Certification: Review and certify your logs daily to ensure accuracy.