Most drivers must follow the Hours of Service Rules and Regulations if they drive a commercial motor vehicle (CMV).
In general, a commercial motor vehicle (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
- The vehicle is designed or used to transport 9 or more passengers (including the driver) for compensation
- Is transporting hazardous materials in a quantity requiring placards
Source: 49 CFR 395
Hours of Service Rules and Regulations put limits in place for when and how long a driver may operate a commercial motor vehicle.
These limits are designed to make sure that the driver is awake and alert while driving and to reduce the possibility of driver fatigue.
The Federal Motor Carrier Safety Administration (FMCSA) has published a book that contains the Hours of Service Rules and Regulations. This book also has the most frequently asked questions regarding those rules and regulations.