This is wrong and I was surprised to hear them say it was enough in the video.

We don't have car horns and sirens for your eyes. You will often hear something long before you see it. This is important for emergency vehicles. Once you hear it, a good driver will immediately slow down and pull to the side, or delay movement to give space for the vehicle.

Does this mean self driving vehicles can't detect emergency vehicles until they appear on camera? That's not encouraging.