US study reveals drivers using hands-free virtual assistants like Apple's Siri can be distracted by the technology, creating safety hazards.
The study produced for the AAA Foundation for Traffic Safety found that some systems offering hands-free communications for tasks such as navigation or changing radio stations can create "cognitive distractions," which compromise safety.
The research comes amid growing use of hands-free technology, which aims to get drivers to avoid the dangerous use of hand-held phones behind the wheel.
But with the technology offering more complex functions -- such as making dinner reservations or updating social media profiles -- these virtual assistants have their own perils.
"Technologies used in the car that rely on voice communications may have unintended consequences that adversely affect road safety," said Peter Kissinger, president and chief executive of the foundation.
"The level of distraction and the impact on safety can vary tremendously based on the task or the system the driver is using."
The study by researchers at the University of Utah found that Siri was particularly distracting when it was used for certain tasks such as updating Facebook or Twitter feeds.
The study found that when performing commonly used tasks, Siri generated a "category 4" level of distraction on a five-point scale, which was the highest in the research.
By contrast, some automakers' virtual assistants performed better. Measuring the most common voice-based interactions -- changing radio stations and voice dialing -- the researcher gave Toyota's Entune system a low distraction rating of 1.7.
Other systems tested included the Hyundai Blue Link (rating 2.2), the Chrysler Uconnect (rating 2.7), Ford Sync (rating 3.0), Mercedes Ccommand (rating 3.1) and Chevrolet MyLink (rating 3.7).
One factor affecting the rate of distraction was the accuracy of voice detection. Systems with low accuracy and reliability generated a high level of distraction.
"It is clear that not all voice systems are created equal, and today's imperfect systems can lead to the perfect storm for driver distraction," said Beth Mosher of AAA, which is also known as the American Automobile Association.
"We already know that drivers can miss stop signs, pedestrians and other cars while using voice technologies because their mind is not fully focused on the road ahead. We now understand that current shortcomings in these products, intended as safety features, may unintentionally cause greater levels of cognitive distraction."
AAA said it urges vehicle and device manufacturers to use the study to improve their voice systems to promote road safety.