I listen to play lists whilst driving. Typically I might have a tablet that I use. The icons for changing songs are tiny and I really shouldn't be trying to find them whilst behind the wheel. I'd love an app with massive control buttons so I'd be able to change songs as easily as I'd change radio channels.
A similar idea has already been suggested here: A SAFE car mode for mobile apps
Please leave your comments/kudos there to support the idea.