I’ve used a similar system which needed me to hold it down for 3 seconds. I think you’ve got a great point there, its not only inconvenient, but dangerous to an extent.

As a user of such a radio, and being a usability enthusiast, I didnot actually go ahead and find the mute button. Why? because the same button that shuts it off, had the volume control for me to turn down to zero. My point being, users are not involved in figuring out their car radio, god knows they’ve got enough appliances to get ‘used to’. Make it as simple as possible, while trying to balance out aesthetics.

As for the mute button…point taken. But it’s not really findable by touch. So it’s not salient.

And I don’t agree about pulling over to power off. I think that’s an apologist position; a car radio should be designed to be powered off while driving. Make a phone call is a different matter. That should be done while stationary.

This button also powers off the radio. It’s designed so you don’t accidently power off the stereo if you hit the button.

When do you power off your radio while driving? If you want to shut the thing up hit the mute button – it doesn’t require holding down for 3 seconds. If you want to power off, pull over and take your time. While you’re at it, you can use your cell phone.