HOS (Hours of Service)
Federal limits on how long a commercial driver may drive and be on duty — recorded by ELDs and a decisive input to whether a load can legally make its appointment.
How it works — and why it matters
The core FMCSA property-carrier rules: a driver may drive up to 11 hours within a 14-hour on-duty window, must take a 30-minute break after 8 cumulative hours of driving, needs 10 consecutive hours off duty before the next shift, and operates inside 60/70-hour weekly limits. Since the ELD mandate, these hours are recorded electronically and are available to dispatch systems through ELD APIs.
HOS is the reason a truck 300 miles out is not necessarily five hours away — if the driver's clock runs out mid-route, the arrival moves by a full rest period. Dispatch decisions, tender acceptance, and any ETA worth publishing all depend on reading the driver's remaining hours, not just the truck's position.
Related terms
See it in practice: Tranztec Predictive ETA Tracking — HOS-aware ETAs →