A carrier must not allow a driver to drive if the driver has accumulated how many hours of 'driving time'?

The correct answer is based on the regulations concerning hours of service for drivers within the National Safety Code. A driver is not permitted to drive if they have accumulated more than 13 hours of 'driving time' within a given duty cycle. This rule is in place to ensure that drivers do not operate a vehicle while fatigued, which can significantly increase the risk of accidents.

In this context, 'driving time' refers specifically to the hours spent actively driving the vehicle, as opposed to other duties like vehicle maintenance or rest. Ensuring that drivers adhere to this limit helps maintain safety standards on the roads by preventing the dangers associated with driver fatigue.

Understanding the implications of this regulation highlights the importance of managing driving time effectively. It also reinforces the need for carriers to monitor their drivers' hours closely, ensuring compliance with the established safety standards.