HOS (Hours of Service)

Hours of Service (HOS) regulations are a set of federal rules administered by the Federal Motor Carrier Safety Administration (FMCSA) that govern how many hours a commercial motor vehicle (CMV) driver can be on duty and behind the wheel. The primary purpose of these regulations is to combat driver fatigue, which is a leading contributor to serious trucking accidents.

Under current HOS rules, property-carrying drivers may drive a maximum of 11 hours after 10 consecutive hours off duty. They must not drive beyond the 14th consecutive hour after coming on duty, and must take a 30-minute break after 8 cumulative hours of driving. The 60/70-hour limit restricts total on-duty time over a 7- or 8-day period, with a 34-hour restart option to reset the weekly clock.

HOS compliance is tracked using Electronic Logging Devices (ELDs), which automatically record driving time based on engine data. Violations of HOS rules can result in out-of-service orders, civil penalties, and negative impacts on a carrier's CSA scores. Proper HOS management is critical for both safety and operational efficiency, as running afoul of the regulations can lead to costly delays and legal consequences.