This morning as I was driving to work thinking about speed sensors, I realized that speed-controlled volume would be a very Bad Thing.

Reason:

When I am on a well-paved road, such as the stretch of highway 20 between my home and work, the car is very quiet, even at very high speeds.

When I am on a poorly-paved road, such as the stretch of interstate 80 to the west of Truckee, the road noise is deafening, regardless of speed.

So I would much rather see a volume control based on an exterior mic mounted under the car measuring road noise.

I'd love to implement a speed sensor for other reasons, but not for volume control.