I've been reading about this a bit and it looks like the OS probably still has "dock support", but out of the box the phone has no way to trigger it.
Supposedly if you run
am broadcast -a android.intent.action.DOCK_EVENT --ei android.intent.extra.DOCK_STATE 2
from the terminal (or `adb shell`) you'll make the phone think it's hooked up to a car dock. (I think state "0" is no dock, and "1" is desk dock)
I plan to play with it today. If it works, it should be possible to automate it or make a home-screen shortcut with Script Manager or similar. I guess you could probably also trigger it from an NFC tag? Not sure how those work, still reading.