Is it true that a driver of an authorized emergency vehicle must be responding to an emergency or pursuing a suspect to operate in emergency mode?

The statement is true because the operation of an authorized emergency vehicle in emergency mode is contingent upon the vehicle responding to a clear emergency situation or actively pursuing a suspect. This requirement underscores the primary purpose of emergency vehicles, which is to provide urgent response capabilities in critical situations, such as accidents, fires, or criminal activity. When an emergency vehicle is responding in this mode, it is allowed to exceed certain traffic regulations, such as speed limits or traffic signals, to respond in a timely manner.

In terms of the phrases in the other options, simply having a siren or relying on the yielding of other vehicles does not, by themselves, constitute a valid reason to operate in emergency mode. The legality and appropriateness of engaging emergency protocols depend explicitly on the nature of the response or the pursuit, aligning with standard regulations governing emergency vehicle operation.