Final answer:
The safest time to change a radio station while driving is when stopped at a red light to prevent distractions. The provided scenarios, while important for understanding rules of the road and the Doppler shift, are not directly related to the main question about radio station adjustments.
Step-by-step explanation:
The best time to change the radio station while driving is indeed when you're stopped at a red light. This allows you to focus on the task without it interfering with your driving responsibilities since your vehicle is stationary and you are not engaging in potentially dangerous multitasking. While the scenario provided discusses an emergency situation where the rules of the road might be bent for the greater good, such as going through a red light during a low-traffic time to get a pregnant woman to the hospital, it is unrelated to the safety of changing radio stations while in normal driving conditions.
In terms of the Doppler shift, this is a phenomenon where the frequency of a sound wave changes for an observer moving relative to its source. In practical terms for drivers, if you hear the Doppler shift in an emergency vehicle's siren, you can determine if the vehicle is approaching or receding from your position. This information is crucial so that you can safely pull over and allow the emergency vehicle to pass. However, this principle is not directly related to the act of changing a radio station while driving.