Final answer:
When not driving a placarded vehicle, shipping papers must be kept in a pouch on the driver's door or on the driver's seat, ensuring quick access for emergency responders.
Step-by-step explanation:
When the driver of a placarded vehicle is not behind the wheel, the shipping papers must be readily accessible. The shipping papers should not be left in the glove compartment or under the seat, nor kept on the driver at all times. According to the Hazardous Materials Regulations, the proper location for the shipping papers is either in a pouch on the driver's door or on the driver's seat when the driver is out of the vehicle. This requirement ensures that first responders have immediate access to the shipping papers in the event of an emergency.