First, there was U.S. Transportation Secretary Ray LaHood, who in recent weeks has been lambasting automakers for not doing more to combat "distracted driving."

Then there was General Motors, which, despite LaHood's ire, announced last week that it will move forward with plans to incorporate Facebook functionality into its OnStar system.

And then there's Ford (NYSE: F), whose SYNC in-car "infotainment" system is set to receive the ability to connect to Twitter shortly.

Is in-car tweeting a step too far? And if not, what about Facebook? Will the industry be able to fend off the regulators?

Ford draws a line, sort of
In the wake of GM's Facebook announcement, Ford hastened to say that it has "no plans" to add a Facebook function to SYNC's already-impressive list of features. And although it's going forward with previously announced plans to add a Twitter connection, Ford made a point of noting that the feature will be limited: SYNC will read your friends' tweets aloud, but you won't be able to reply to or post tweets yourself.

SYNC, of course, is an elaborate music/information/connectivity system available as an option on nearly all Ford vehicles. It was developed using a Microsoft (Nasdaq: MSFT) platform and Sony's (NYSE: SNE) Gracenote system, and it's updated frequently, mostly for current owners. SYNC is tremendously important to Ford, because it's been drawing large numbers of new customers to the company and contributing to a sharp increase in per-vehicle revenue.

But it's also in danger of becoming a regulatory target. LaHood, who has been campaigning against in-car phone use for a while, has called out SYNC as an example of a trend toward more in-car distractions that could cause accidents. Current research on in-car distractions at the National Highway Traffic Safety Administration could lead to bans on in-car electronic communications, even voice-activated ones, according to a Bloomberg report.

How far will the feds go?
My sense is that LaHood would love to ban in-car phone use by drivers, period, among other things -- but as a matter of law, such a ban would probably have to be enacted on a state-by-state basis. His efforts have contributed to a trend toward state-level bans on in-car texting and restrictions on phone use in some 30 states already. But LaHood has recently made it clear that his concerns extend to systems such as SYNC, which allow drivers to control audio, GPS, and connectivity features with voice commands.

Ford's response is that SYNC is safer because it's a voice-activated system. Fiddling with a complicated stereo or navigation system is also a distraction for drivers, the company points out. By enabling voice commands for all of these features, the SYNC system helps keep drivers' eyes on the road and improves safety -- or so the argument (and Ford's research) goes.

It certainly sounds like a reasonable argument, and the safety angle has no doubt contributed to SYNC's success. And, as always in the auto business, that success is spawning imitators. GM, which has never hesitated to copy a competitor's good idea, is remaking its OnStar system in a SYNC-like image. Adding the ability to listen to (or make) Facebook updates is a key part of GM's effort to position OnStar as a SYNC competitor.

But LaHood has already called out OnStar. GM, like other companies moving into this space, runs the risk of going one feature too far -- and igniting a regulatory firestorm.

The distraction-free driver
Some would argue that the ultimate answer to in-car technological distractions and other safety concerns is to build cars that drive themselves. Is Google's (Nasdaq: GOOG) fleet of self-driving Toyota (NYSE: TM) Priuses the true future of the automobile?

Speaking as a car lover, I hope it doesn't come to that. And I would hate to see the federal government try to do something like banning in-car phone use. But LaHood seems devoted to this cause, despite skepticism from august sources such as the Insurance Institute for Highway Safety, which recently released a study suggesting that banning in-car texting didn't actually reduce accidents.

Clearly, automakers will have to tread carefully if they want to preserve their popular -- and lucrative -- in-car infotainment suites.