Most drivers of commercial vehicles are required to maintain a log book to record their hours of service.
Interstate: Maximum driver hours for property-carrying drivers involved with interstate commerce (that crosses state lines) have changed as of August 2005, to take effect October 1, 2005. For details, go to: Federal Motor Carrier Safety Administration - Hours of Service Regulations or go to: Code of Federal Regulations.
Intrastate: Maximum driver hours for intrastate commerce (within California) have not changed. For intrastate requirements, go to California Dept of Motor Vehicles, the California Vehicle Code Section 34501.2, and/or the California Code of Regulations (select Title 13, Division 2, Chapter 6.5, Article 3, Section 1212 "Driver Hours of Service").
For more information about driver hours of service, contact the Commercial Vehicle Section of the California Highway Patrol (CHP) at (916) 843-3400.