Why would someone have a K restriction on their CDL?

A K restriction on a Commercial Driver's License (CDL) indicates that the driver is only authorized to operate a specific type of commercial vehicle, typically one that does not require a hazardous materials endorsement. This restriction may be applied if the driver has not passed the necessary tests for transporting hazardous materials or has not obtained the required background check. It ensures that drivers operate vehicles appropriate to their qualifications and training, maintaining safety standards on the road.