Speaking with the throngs on Reddit, Android engineer Dan Morrill confirmed that the Samsung Galaxy Nexus can't support USB mass storage. Unlike other Android devices equipped with an SD card, your vehicle's infotainment system would mount your smartphone and recognize it as a drive. That's not the case with the Galaxy Nexus due to a new partition setup.
Thankfully, other devices upgraded to Android 4.0 (Ice Cream Sandwich) won't be affected by the issue, so Nexus S owners can sleep soundly. Of course, Bluetooth playback will still be supported, so that long drive to Grandma's house on Turkey Day won't be a tunes-free affair.
Interestingly, one automaker should be immune from the issue: Ford. The automaker's SYNC 1.0 and 2.0 infotainment systems supports MTP (Media Transfer Protocol), which the Galaxy Nexus uses to transfer files with Windows machines. And as you'll recall, Microsoft co-developed SYNC with Ford. However, representatives from Ford haven't been able to confirm if the new Nexus works with their system, and we've yet to receive word from other automakers about the issue.