Hands-Free No Safer Than Handheld?

Many people consider hand-free in-car mobile devices to be risk-free. However, a 2006 study from Jacksonville State University (Active Prompting to Decrease Cell Phone Use and Increase Seat Belt Use While Driving) says that,

[c]ompared to drivers who do not use cell phones, drivers talking on cell phones miss twice as many traffic signals, are more likely to swerve into the next lane (46%), tailgate (23%), have close calls (18%), and run red lights (10%)  … The use of a hands-free phone results in an equal level of distraction, but the radio, passenger conversation, and books on tape do not interfere with driving to the same extent …

The paper cites numerous other studies that have reached this conclusion.

And from a 2000 study at Harvard, cited in a suppressed body of research conducted by the US Department of Transportation in 2003 and recently published in the New York Times (Documents: Department of Transportation’s National Highway Traffic Safety Administration):

It is not clear whether hands-free cellular phone designs are significantly safer than hand-held designs, since it may be that conversation per se rather than dialing/handling is responsible for most of the attributable risk due to cellular phone use while driving.

So why have government and industry embraced hand-free mobile devices as a resonable-risk alternative to simply working to prevent all form of extra-vehicular communication?

Could it be that lawmakers, politicians and technology designers are simply too addicted to their own devices to care?