Hours of Service (HOS) regulations are issued by the Federal Motor Carrier Safety Administration (FMCSA) and govern the working hours of anyone operating a commercial motor vehicle (CMV) in the United States. These regulations apply to truck drivers, commercial and city bus drivers, and school bus drivers who operate CMVs. These rules limit the number of daily and weekly hours spent driving and working, and regulate the minimum amount of time drivers must spend resting between driving shifts. For intrastate commerce, the respective state's regulations apply.  HOS can be used as part of your base GPS vehicle tracking or telematics application