Final answer:
When you see or hear an emergency vehicle with activated lights or sirens, you should pull over to the side and stop to allow it to pass safely.
Step-by-step explanation:
When you see an emergency vehicle with its lights or sirens activated, it is essential to follow the appropriate actions to ensure their quick and safe passage. According to traffic laws, you should not run towards or alongside the ambulance. Instead, when you hear the Doppler shift of an ambulance siren indicating it is approaching, you should pull over to the side of the road and stop, allowing the emergency vehicle to pass. This principle applies whether you are driving a car or standing on the sidewalk. When the emergency vehicle is in front of you, the frequency you observe will most closely match the actual frequency of the siren, according to the GRASP CHECK principle.