Keep your eyes on the road

Voice-based, in-vehicle navigation systems are safer than those relying on visual/manual interactions.

June 21, 2011
by Kara Kuryllowicz

Canadian Automotive Review: JUNE 2011

It’s no surprise that a recent study by OnStar and the Virginia Tech Transportation Institute (VTTI) found that voice-based, in-vehicle navigation systems are safer than those relying on visual/manual interactions.

“The less you take your eyes off the road, the safer you’ll be because research shows that 95 percent of the information required to drive safely comes through the eyes,” says Raynald Marchand, general manager, programs, Canada Safety Council, an Ottawa-based non-government organization. “A visual awareness of other vehicles and the road has the greatest impact on safe driving.”

The OnStar-commissioned study evaluated a cell phone-based navigation application, a personal navigation device (PND), OnStar Turn-by-Turn directions and OnStar Destination Download, as well as printed driving directions. Researchers found that voice-based OnStar Turn-by-Turn directions allowed drivers to keep their eyes on the road longer, required the shortest amount of time to enter a destination and resulted in better overall vehicle handling.

The study showed that the two OnStar systems required significantly less mental effort than the personal navigation device and cell phone application. Drivers using OnStar simply push a button to connect with a human advisor who will locate the destination and download the turn-by-turn directions to the vehicle. Drivers can also use OnStar’s eNav to plan their routes ahead of time and send the directions to their vehicles with just one click.

Must be intuitive
“A voice-based navigation system with turn-by-turn directions could be quite helpful, but it must be well-designed and intuitive with accurate, reliable  content,” says Dr. Joanne Harbluk, a human factors specialist with Transport Canada. “For example, if users have to repeat commands or have trouble understanding the voice, it’s distracting and frustrating, which can impair driving performance.”

While an intuitive, well-designed and accurate navigation system is an effective tool, such conveniences may still be considered a distraction. In the 2011 article, “Distracted Driving: So What’s the Big Picture”, author Robyn Robertson, president and CEO of the Traffic Injury Research Foundation, notes that because humans are serial processors of information, they can consciously focus their attention on only one task at a time. People believe that they can rapidly switch their attention from task to task, but the reality is that when multi-tasking, no task receives the optimal attention or focus.

Studies conducted by Transport Canada showed that when drivers are distracted, even by voice interactions, they tend to focus on a narrow portion of the forward view. Drivers who do not scan appropriately run the risk of not being aware of their driving environment.

“Inattention blindness”
Meanwhile, Carnegie Mellon University researchers examined MRI pictures of drivers’ brains while they decided whether spoken statements were true or false. The MRIs showed that activity in the brain’s parietal lobe (an area associated with navigation and spatial processing) decreased 37 percent and activity in the occipital lobe (associated with processing visual data) also dropped. Evidently, the more attention paid to secondary tasks, the more drivers start to suffer from “inattention blindness”, which means they may be looking, but it doesn’t mean they’re actually seeing.

To maximize the effectiveness of navigation tools and ensure attentive, safe driving behaviours while navigating, Dr. Harbluk and Marchand shared these tips with Canadian Automotive Review.

  1. Research navigation systems the way you would any other electronic device. Expert and consumer reviews will provide points worth considering, as will discussions with colleagues, friends and family who have experience using such systems.
  2. Test the device in the store if at all possible. It takes time to become accustomed to any system, but if you absolutely hate anything about the navigation tool, you should probably keep shopping.
  3. Consider a system that tells you the name of the street onto which you will turn and provides an expected arrival time.
  4. Post purchase, follow the manufacturer’s installation instructions to securely attach the device to the vehicle’s interior wherever it won’t  block the driver’s view of the road.
  5. Read the manual and practice programming and using the system on routes you know before relying on it to reach an unknown destination.
  6. Always pre-program destinations and if you need to add or alter a destination, pull over somewhere safe or have a passenger do it.
  7. A navigation system’s simple turn-by-turn directions can be very useful, but drivers still need to think about what they’re being told to do.