Not long ago, motor-mouthed drivers thought hands-free technology would provide the solution for safe driving while texting and talking — and many still do.

Apple on Monday revealed an updated operating system for its mobile platform that many car manufacturers intend to integrate into the dashboard by next year, offering a panoply of technology services to the driver by voice command. And by 2018, voice-activated computer dashboard systems will become standards, with a five-fold increase in the proportion of new cars with such systems.

However, scientific research since 2006 has shown that hands-free technology is just as distracting as handheld cell phones while driving a motor vehicle, and the distractions from cellular technology become increasingly worse with improved applications. Who would have thought online banking would be so easy and convenient at 60 miles per hour?

David Strayer, a psychology professor at the University of Utah, led a recent study on behalf of AAA, formerly known as the American Automobile Association. "Our research shows that hands-free is not risk-free," he said in an interview. "These new, speech-based technologies in the car can overload the driver's attention and impair their ability to drive safely," said Strayer. "An unintended consequence of trying to make driving safer — by moving to speech-to-text, in-vehicle systems — may actually overload the driver and make them less safe."

The problem with driver distraction may be getting worse rather than better, Strayer said.

"Just because you can update Facebook while driving doesn't mean that it is safe to do so," he said. "Don't assume that if your eyes are on the road and your hands are on the wheel that you are unimpaired. If you don't pay attention then you are a potential hazard on the roadway."

Strayer first demonstrated the dangers of hands-free cellular technology in a 2006 study, though the message failed to impress the general public — with many motorists believing hands-free devices to be safer with improved technology.

With the imprimatur of AAA, however, Strayer hopes people realize they're putting their lives, and others, at risk by using voice-activated phone, email, texting, and social media technologies while driving a motor vehicle. But the problem just keeps getting worse.

"There is a looming public safety crisis ahead with the future proliferation of these in-vehicle technologies," Robert L. Darbelnet, president and CEO of AAA, said. "It's time to consider limiting new and potentially dangerous mental distractions built into cars, particularly with the common public misperception that hands-free means risk-free."

In the study, Strayer and his research team measured brainwaves, eye movement, and other metrics to assess a driver's mental workload as they attempt to multitask. Using cameras mounted inside a test car, they traced eye and head movement of drivers, and used another device to record driver reaction time in responses to cues in their field of vision. As the drivers operated the instrumented car, their brain waves were recorded using a custom skull cap outfitted with an electroencephalograph (EEG).

Interestingly, the level of technological progress has increased the level of distraction to the driver. Listening to the radio, once thought to be distracting in the early ages of automobile development, was least distracting. A cell phone conversation rose to the next level. But most distracting of all was verbal interaction with a voice-activated email application, researchers reported.

In light of these findings, AAA urged the automotive and electronics makers to limit voice-activated technology to core driving-related activities, such as climate control, windshield wipers, and cruise control — with Twitter-feed updates completely out of the question.

"This study constitutes the most in-depth analysis to date of mental distractions behind the wheel. AAA is hopeful that it will serve as a stepping stone toward working in collaboration with automakers to promote our shared goal of improving safety for all drivers," said Darbelnet. "Specifically, these increasingly common voice-driven, in-vehicle technologies should be limited to use for just core driving tasks unless the activity results in no significant driver distraction."

Apple unveiled its plans for the "iOS in the Car" on Monday at the Worldwide Developers Conference in San Francisco.