Hours of service
Also called HOS
Hours of service are the federal limits on how long a commercial driver may drive and remain on duty before rest is required, designed to reduce fatigue-related crashes.
Last reviewed · by the fleetchart dispatch desk
The rules govern maximum driving time within a duty period, the total on-duty window, required rest breaks and weekly limits, with provisions for splitting rest in the sleeper berth.
Hours are effectively inventory. A load that consumes a full duty period for modest revenue has cost more than its fuel — it has cost the capacity to run something else.
Detention consumes this inventory without paying for it, which is why long dock waits are more expensive than the detention rate suggests.