Even switching to hands-free texting may not reduce the risk of distracted driving.

Even as more states move to bar motorists from texting while driving, a growing number of automakers have been adding supposedly safer voice-to-text features to their vehicles. But a new study by the Texas Transportation Institute warns that the newer technology is just as likely to leave drivers distracted and at risk of a crash.

Distracted driving is responsible for an estimated 11% of all highway deaths, according to the National Highway Traffic Safety Administration, and texting is generally seen as one of the worst – and growing — problems. The Texas study cites industry data showing Americans send 6.1 billion text messages a day, and other studies have indicated that a sizable share of U.S. motorists – including a significant majority of younger drivers – text behind the wheel.

With more and more states barring the use of handheld phones, whether to make a call or to text, the auto industry has been trying to fill the gap with hands-free technology such as Bluetooth calling and new voice-to-text apps.  But despite being billed as a safer alternative, the new study indicates that texting in any form is a dangerous distraction.

“Results indicate that driver reaction times were nearly two times slower than the baseline condition, no matter which texting method was used,” according to Christne Yager, the associate transportation researcher at the Texas Transportation Institute.

The study took 43 licensed drivers between the ages of 16 and 60 and placed them behind the wheel of a 2009 Ford Explorer, each driving on a closed course four times for about 10 minutes. They were asked to drive once while focusing on the road, once while texting manually, and then once each using an iPhone voice-to-text app and an Android phone using voice-to-text.

Though drivers perceived the voice-operated systems to be safer, Yager says “driving performance suffered equally.” In fact, in some cases, manual texting actually took less time to complete.

“That is not surprising at all,” John Ulczycki, vice president of the National Safety Council, told USA Today. Part of the problem, he warned, is that the voice-to-text technology isn’t necessary perfected and can create its own distractions when messages come out garbled. As a result, those using such apps are “still taking their mental concentration off the road.”

While just one small study, the results of the Texas Transportation Institute research could complicate an already complex issue.  Ray LaHood, the U.S. Secretary of Transportation, has declared distracted driving an “epidemic,” and called for a crackdown on the use of handheld devices while driving, but there is growing concern about the use of hands-free technology, as well.

The National Transportation Safety Board has outlined an aggressive plan to eliminate most high-tech distractions from the automobile, including not just Bluetooth systems but even most onboard navigation devices.

That proposal generated sharp pushback from both the communications and automotive industries but also led to a search for safer technologies, with an emphasis on voice-based systems. The new Mercedes-Benz CLA, for example, will allow a motorist to not only exchange voice-to-text messages, but even use a voice app to listen to and respond to Facebook postings.

Such technologies could be threatened if the Texas research is replicated by other studies.