How long should a phase display time never be less than?

A phase display time should never be less than 2 seconds because this duration allows adequate time for other road users to perceive and respond to the emergency vehicle's presence. Shorter display times may not provide sufficient warning, especially in high-traffic or complex environments where drivers may need additional time to notice and react appropriately to the situation.

This is crucial for ensuring safety as it reduces the likelihood of accidents caused by drivers inadvertently obstructing or failing to yield to emergency vehicles. In operational contexts, allowing for this minimum time ensures that both the emergency personnel and the general public are protected during critical situations.