A lengthy report from AAA shows that using the iPhone’s Siri voice command technology hands-free in the car provides a high-level of distraction to drivers. Though it’s likely that using Siri is less distracting to a driver than actually holding a phone and performing tasks, it’s a good reminder to drivers that even hands-free systems are not distraction-free.

The research team had drivers use Siri “hands (and eyes)-free” to listen to and send text messages, update their Facebook or Twitter status, and to modify and review calendar appointments.

The report, available as a PDF, found using Siri for these more complicated tasks is significantly more distracting than other in-car tasks, like adjusting the radio/temperature or simply listening to text messages.

Siri’s power is something of a downfall, because users can perform more advanced tasks, such as editing calendar appointments or sending and receiving email. This makes using it more distracting than a voice-controlled phone with more limited capabilities.

“To understand the workload rating associated with interacting with Siri, it is first useful to consider what is not causing the effect. The high level of workload is not due to visual/manual interference. Participants never looked at nor touched the iPhone during the session; in fact, the experimenter performed all manual interaction with Siri. As such, this indicates that the impairments were cognitive in nature, associated with the allocation of attention to the task.”

The research shows that simpler tasks — like listening and composing messages, or simply listening to messages without writing back — are much less distracting.

In iOS 8, released last month, Apple added a new feature to Siri to enable more hands-free operation. When plugged in to power, the iPhone and iPad now respond to the voice query “Hey, Siri” even when the screen is locked. This means that a driver can control their iPhone via Siri without ever physically touching the phone.

Queries like “Hey Siri, text my wife ‘I’ll be home in 15 minutes'” or “Hey Siri, when does the Red Sox game start?” will be answered promptly by the phone.

The AAA report did have some criticisms of Siri, in particular (other voice-recognition systems, including Android’s Google Now or Cortana on the Windows Phone weren’t tested). Researchers found that sometimes Siri would respond differently to seemingly identical commands, or minor changes to phrasing would result in a failure, requiring drivers to restart their commands. It also sometimes called the wrong person from a contact list, requiring additional corrections.

The report also notes that some participants “reported frustration with Siri’s occasional sarcasm and wit.”

Though Siri provides high levels of distraction, it’s likely that users are still better off using it than they would be trying to use an iPhone in their hand while driving. For iPhone users, I highly recommend you install iOS 8 and use a power cord in the car to take advantage of the new “Hey, Siri” commands.

Does your company require its employees to use hands-free systems when driving? Let us know how you use Siri in the discussion thread below.