Hands-free voice-activated controls are not safe according to studies by the American Automobile Association Foundation

This article is more than 5 years old

This article is more than 5 years old

Voice-activated systems designed to keep drivers’ eyes on the road are as distracting as making a mobile phone call while driving, two studies have found.



The research by the American Automobile Association Foundation (AAA) discovered that voice control systems, which allow drivers to control functions within the car like changing the radio station or making phone calls, were just as distracting as making a handheld phone call, which is illegal in the UK.

“Poorly executed voice systems may … [impose] high levels of mental demand on drivers with the potential to also incur long glances away from the roadway in order to check system status and understanding,” says the research paper.

Voice tasks: tougher than talking

The researchers tested six built-in systems, including the Ford MyFord Touch voice-control system, as well as Apple’s Siri voice assistant on an iPhone, on a sample of 45 drivers.

For the built-in systems, which were installed in US cars made in 2012 and 2011, test drivers were asked to drive a nine-minute loop through a residential neighbourhood while being instructed to dial a 10-digit number, call a contact, change the radio station or play a CD using the hands-free voice-control systems.

The researchers measured the driver’s mental capacity, reaction time and heart rate during the tests. They found that not all the in-car systems were the same, with some significantly more distracting than others, but the majority of them were as distracting as a demanding mental maths problem.

“This indicates that common voice tasks are generally more demanding than natural conversations, listening to the radio, or listening to a book on tape,” the researchers wrote.

Siri and natural language is even more distracting

Siri, Apple’s natural-language voice-control system and assistant, was found to be even more distracting than the fixed-command control systems.

In a simulator, interacting with Siri caused two virtual crashes despite researchers in the vehicle with the driver pushing the touchscreen buttons when prompted, allowing the driver to interact with Siri without looking at the iPhone’s screen or tapping any buttons.

Drivers used natural language to send and receive text messages, update social media and review calendar appointments using Siri. A lapel microphone was used so that drivers could talk at normal volumes to the smartphone.

“The participant neither looked at nor made physical contact with the iPhone during these interactions,” wrote the researchers. “Even so, the workload ratings exceeded category 4 on our workload scale – the highest ratings that we have observed for any task.”

The researchers used Siri as an example of all-natural language systems, concluding that others, including Google and Microsoft’s voice assistants, would be similarly distracting.

They found that the concentration required for natural language interaction was higher than set voice controls. Siri’s inconsistent responses to the same commands – often highlighted elsewhere as the “human element” of Siri – also caused more distraction, while some actions required exact phrases despite the natural-language setup.

“Some participants also reported frustration with Siri’s occasional sarcasm and wit,” said the AAA researchers.

The studies conclude that while well-designed voice control systems with minimal steps and accurate recognition could potentially be less distracting than manual controls, clicking a button or flicking a switch was much faster and caused fewer issues.

• Microsoft’s ‘Star Trek’ voice translator available before the end 2014

• Battle for the car: will Google, Apple or Microsoft dominate?