This was originally posted by the US Department of Transportation Federal Motor Carrier Safety Administration . It is being reposted to inform you about changes in the hours of service regulations. The Hours-of-Service regulations (49 CFR Part 395) put limits in place for when and how long commercial motor vehicle (CMV) drivers may drive. These regulations are based on an exhaustive scientific review and are designed to ensure truck drivers get the necessary rest to perform safe operations. FMCSA also reviewed existing fatigue research and worked with organizations like the Transportation Research Board of the National Academies and the National Institute for Occupational Safety in setting these HOS rules. The regulations are designed to continue the downward trend in truck fatalities and maintain motor carrier operational efficiencies. Although the HOS regulations are found in Part 395 of the Federal Motor Carrier Safety Regulations, many States have identical or similar regulations for intrastate traffic. Who must comply with the Hours-of-Service Regulations? Most drivers must follow the HOS Regulations if they drive a commercial motor vehicle, or CMV. In general, a CMV is a vehicle that is used as part of a business and is involved in interstate commerce and fits any of these descriptions: Weighs 10,001 pounds or more Has a gross vehicle weight rating or gross combination weight rating of 10,001 pounds or more Is designed or used to transport 16 or more passengers (including the driver) not for compensation Is designed or used to transport 9 or more passengers (including the driver) for compensation A vehicle that is involved in Interstate or intrastate commerce and is transporting hazardous materials in a quantity requiring placards is also considered a CMV. Summary of the Hours-of-Service Regulations The following table summarizes the HOS regulations for property-carrying and passenger-carrying CMV drivers.