We've reviewed a number of smartphone apps that read texts aloud to drivers -- apps like, PhoneGuard, and SafeCell -- but we've seen very few text-to-speech applications from automakers themselves. Ford is a notable exception.

Through its popular Sync infotainment system, Ford recently began offering text-to-speech functionality on most model-year 2012 vehicles (Ranger not included). Today, we're happy to announce that this feature has begun rolling out as an upgrade for older vehicles equipped with Sync.

To activate text-to-speech, Ford owners simply need to download the latest Sync update to a USB drive and follow the instructions for upgrading. At the moment, the upgrade is limited to vehicles from the 2010 and 2011 model years, but Ford says it will come to older vehicles soon.

There is, however, one small problem: the protocol that makes Ford's text-to-speech feature possible doesn't work with every phone. In fact, remarkably few phones can make use of it: a handful of LGs, Motorolas, Nokias, Samsungs, and Sonys. iPhones? Not so much. (For a complete list of phones and Sync compatibility, check this PDF.)

Sync's Mark Porter thinks this will change in the near future, as more studies reveal the dangers of texting and driving -- studies like the one from Texas A&M showing that texting doubles driver reaction time. That data, combined with a proliferation of laws against texting and driving, should result in more consumers demanding the feature from handset manufacturers. Stay tuned.