More than a year ago, Institute researchers estimated the safety potential of crash avoidance features but couldn't say then if drivers would welcome the extra help. Now a new Institute survey reveals drivers are using their vehicles' crash avoidance features and would get them again. Drivers generally report safer habits instead of riskier ones. These features' success hinges in part on how drivers respond to and use them.
The Institute surveyed Volvo and Infiniti owners because early in the race these automakers adopted crash avoidance technology. Volvo was one of the first to put many of the features on U.S. cars, and Infiniti was first in the United States to market a system that steps in for drivers to prevent lane drift.
The 2007-08 model Volvos in the study had forward collision warning with automatic braking, lane departure warning, side view assist, and active headlights. The 2005-09 Infinitis had lane departure warning or lane departure warning coupled with prevention. The Institute previously identified forward collision and lane departure warning as the systems with the best potential to avoid or mitigate crashes, including fatal ones (see Status Report special issue: crash avoidance features, April 17, 2008).
Overall survey responses were positive. Most Volvo and Infiniti owners keep the systems on, a key finding because they must be active to deliver benefits. The exception is Infiniti's lane departure prevention, which has to be turned on each time a vehicle starts. At least 75 percent of people who use each system think the feature helps them be safer drivers and would want it again.
All but active headlights alert drivers to potential crashes with either audible or visual alerts or both. "Annoying" is how some owners described the alerts, either because they consider them false or unnecessary or just jarring. Malfunctions in bad weather or on poorly marked roads were noted.
"The technology is so new that there are bound to be bugs, and drivers will need to get used to the features," says Anne McCartt, Institute senior vice president for research and an author of the study. "What's important is the majority of Volvo and Infiniti owners are happy with their systems, and even those who find certain aspects frustrating don't hit the off button."
Volvo's forward collision warning alerts drivers when they get too close to vehicles ahead and automatically applies brakes if a collision is judged unavoidable. Radar measures the distance between vehicles, and a camera distinguishes between vehicles and objects like sign posts. The system works at 20 mph or faster.
Volvo's side view assist, dubbed blind spot information, has rear-facing cameras in the side mirrors to monitor traffic on both sides. Lamps in the windshield pillar by the mirrors light up if a vehicle enters a side blind zone.
Active headlights rotate in the direction of steering as the front wheels turn to improve nighttime visibility on curves. Volvo's lights are bi-xenon, making them brighter than the traditional halogen.
When a driver drifts out of a lane without using a turn signal, Volvo's lane departure warning system sounds an alert. A camera mounted near the center rearview mirror detects lane markings. This system operates at speeds of 40 mph or faster.
Infiniti's lane departure warning activates at speeds above 45 mph, using a camera and speed sensor to recognize lane markings and determine how close the vehicle is to crossing them. Beeps and flashing lights let drivers know they're about to drift into another lane or off the road.
On some newer Infiniti models, drivers can activate a prevention feature that applies the brakes to wheels opposite the lane marker to gently nudge a vehicle back into its travel lane if the driver doesn't respond to an audible warning. When designing lane departure prevention, Infiniti decided that the system's default setting would be off since lane departure prevention intervenes to take action for the driver. In the Institute's survey, 1 in 5 Infiniti owners with lane departure prevention didn't know they had it. Another 1 in 5 Infiniti owners said they never use the feature.
Owner experience with 4 features (percent)
||Forward collision warning (Volvo)
||Side view assist (Volvo)
||Active headlights (Volvo)
||Lane departure warning (Volvo)
||Lane departure warning (Infiniti)
||Lane departure prevention (Infiniti)
|Received warnings perceived as false or unnecessary
|Didn't receive warnings when they believed they should
|Find system annoying
|Believe they are safer drivers with system
|Would want system again
Respondents were more likely to report potentially safer behavior, not riskier practices. For instance, about 70 percent said they drift from their lanes less often because of lane departure warning or prevention. Up to 64 percent said they use turn signals more. This indicates the crash avoidance features might be conditioning drivers to signal intentional lane changes to avoid triggering warnings. Nearly half of drivers with forward collision warning said they keep safer following distances.
Only 5 percent of surveyed owners of Volvos with forward collision warning said they look away from the road more often, and just 2 percent reported following vehicles ahead more closely. Of those with Volvo side view assist, 13 percent said they solely rely on it when changing lanes rather than turning their head to look for the all-clear.
"A concern is that drivers might depend on crash avoidance technology too much. Another is that they'll take a risk they wouldn't otherwise," McCartt points out. "Most people told us this isn't the case. They're using the systems to be safer, not reckless."
Percent of owners who drive with system turned on
Complaints but acceptance
Some professional drivers reviewing early systems reported deactivating them because they were irritating, particularly lane departure warning. So it's no surprise this drew the most complaints. When the Institute asked if owners considered lane departure warning annoying, 25 percent of Volvo drivers and 41 percent of Infiniti drivers agreed it is. Still, 69 percent of both groups reported always keeping the system on, suggesting that even if irksome, it's useful.
A large percentage of owners reported false or unneeded alerts. This was highest for side view assist (74 percent) and lowest for lane departure prevention (10 percent). It's possible that a system may work just fine, but drivers don't think they're about to crash or already recognize a hazard. For example, 6 percent of Volvo owners reported they got a forward collision warning when a vehicle ahead slowed to turn, but these owners thought the warning unnecessary because they were aware of the situation.
McCartt says "emerging features that warn drivers of potential crashes and even take over the driving in some instances won't move from the luxury to mainstream market if they don't win over early adopters. The potential safety benefits are huge, so the survey responses are encouraging. Drivers keep the systems on and use them, despite annoyances. It's an indication that everyday drivers will accept the technology, too. A caveat is that systems drivers must activate seem less likely to be used."