Vehicle systems designed to alert a distracted driver to a road hazard are unlikely to deter a driver from distraction in the future, according to a recent study by the Insurance Institute for Highway Safety. However, the organization also determined that the systems don't inadvertently encourage such behavior by giving the driver a false sense of security.

IIHS researchers sought to determine whether vehicle warning systems were likely to affect driver behavior either positively or negatively. They observed the behavior of several volunteers driving a Honda Accord equipped with warnings for forward collision, lane departure, and excessive speed on curves.

"We hypothesized that collision alerts might lead drivers to focus more closely on driving, but that wasn't the case," said David Kidd, a senior research scientist at IIHS who authored the study. "At the same time, fears that warning systems might have the opposite effect appear to be unfounded."

The study included 108 volunteer drivers between the ages of 20 and 70. These adults spent an initial period driving a vehicle without the warning systems, then drove a vehicle equipped with the features.

A secondary analysis focused on 40 volunteers who were 16 or 17 years old. Half of this group drove a vehicle equipped with warning systems after an initial period of driving without them, while the remaining teenagers drove without a warning system for the entire length of the study.

Researchers collected 10 five-second video clips from within each driver's vehicle every week. Some of the clips were taken when the vehicle was traveling at less than five miles per hour, while others were taken when the vehicle was traveling above 25 miles per hour. Each clip was coded for the presence of 11 secondary behaviors.

Among the drivers whose vehicles were equipped with warning systems, 46 percent continued to engage in at least one secondary behavior while driving. The most common behaviors were talking with a passenger, grooming, talking on a cell phone, or manipulating a smartphone or other device.

Younger drivers were more likely to be distracted than older drivers. Fifty-seven percent of the clips sampled from teen drivers showed at least one secondary behavior, compared to 39 percent among drivers who were 60 to 70 years old.

Drivers were also more likely to engage in a distracting behavior at lower speeds. The volunteers were 21 percent more likely to do at least one secondary task at speeds below five miles per hour than they were at speeds above 25 miles per hour. IIHS says this finding is in line with the results of a 2015 study, which found that drivers were significantly more likely to use a cell phone or eat while stopped at an intersection than if they were moving at an intersection or going into a roundabout.

Even though the study suggests that warning systems have little effect in modifying driver behavior, IIHS says they can still be beneficial. In 2010, researchers determined that 1.9 million crashes and one-third of fatal accidents could be avoided if every vehicle was equipped with a functional crash avoidance system.

"Completely eliminating driver distraction isn't possible," said Kidd. "Warning systems that bring a driver's attention back to the road when a crash is imminent can help keep distraction from turning deadly."