Associate Professor of Computer Science at Drexel University, Dario Salvucci:
A recent GMAC survey reported that 20% of drivers age 18-24 have used an iPod while driving. Knowing how distracting cell phones can be, it may not be surprising that using an iPod while driving can also be distracting. More surprising is the size of the effect. Our study of iPod distraction found that selecting a song on an iPod can degrade performance almost twice as much as dialing a cell phone. Even more surprisingly, selecting a song can degrade performance twice as much as watching a video on the iPod. The level of distraction for iPod use is severe and warrants further consideration as an important source of driver distraction.
And to think the iPhone is both phone and iPod.