Hours of Service

What is HOS? Hours of Service Rules & Definition

What is HOS?

According to the FMCSA, Hours of Service (HOS) refers to the maximum amount of time drivers are allowed to be on duty. This includes drive time and specifies the number and length of rest periods. HOS helps ensure that drivers stay awake and alert while en route. In general, all carriers and drivers operating commercial motor vehicles (CMVs) must comply with HOS regulations found in 49 CFR 395.

Hours of Service rules and definition

The Hours of Service rules (HOS rules) are federal safety regulations that address the maximum amount of time a commercial motor vehicle driver can work in the United States, among other things.

Understanding the Hours of Service rules

The federal Hours of Service regulations are a fairly complex set of safety-related requirements that describe:

  • How long a driver is allowed to drive during a single shift
  • The amount of time a driver can drive during the week
  • When a driver must take a rest break during a work shift
  • How much time off a driver must have between shifts

What is the purpose of the Hours of Service regulations?

Hours of Service rules help promote driver alertness and prevent accidents caused by driver fatigue.

Who must comply with HOS rules?

Motor carriers and drivers must comply with the rules if they move goods or passengers in interstate commerce.  

This means that the CMV either crosses state lines, or the shipment of the goods originated from out of state.

How to demonstrate HOS compliance

Generally, drivers must show their compliance with Hours of Service rules by logging their driving, on-duty, and off-duty time using an electronic logging device (ELD) or paper logs (if the carrier, driver, or vehicle qualifies for an ELD exemption).

Do states have intrastate HOS rules?

Yes. Since states are federally permitted to be more lenient for intrastate commerce, HOS rules can sometimes differ from state to state. 

Generally speaking, intrastate commerce means the goods being hauled originated and are delivered within the state, and the transportation doesn’t fall under the definition of interstate commerce.