Doppler Effect for Physics EC

The horn of the car is being held at a constant honk all the way down the road. The observer stands in the middle of the road to check the change in sound as the car approaches with the horn and as it passes. The sound of the horn starts off quiet, and then the volume of the sound increases as the car gets closer to the observer. The Volume of the horn is at its highest when it is right in front of the observer, and then starts to decrease as the car drives by. This creates the doppler effect of the sound increasing and decreasing as the car approaches and passes the observer.
The observer is the only one who notices the sound difference as the car drives by, the driver in the car hears a constant volume of the horn because they are sitting in the car the whole time, the sound does not approach nor pass them.