Tired of the 'turn signal nanny'

As advanced safety technology spreads throughout vehicle lineups, automakers and suppliers are getting broader feedback about their effectiveness.

Two safety systems illustrate the varying results.

These systems use sensors and automatic braking, sometimes called autobrake, to detect and avoid a likely collision. Insurance Institute for Highway Safety research shows that vehicles with these features are less likely to rear-end another car. 

Consumers who have been saved from a crash become believers, says Dean McConnell, leader of sales, project management and business development for Continental Automotive Systems. 

"This is a case where people see the benefit," McConnell said. "They want to see it work, and they want to have it on all the time." 

Acura spokesman Matt Sloustcher says that, among safety systems, collision mitigation especially wins converts. Sloustcher said: "It's a powerful experience for anyone in a car with [collision mitigation] the first time the system deploys."

This is the most problem-ridden active safety system. David Kidd, an IIHS senior researcher, says the group "had high hopes" for lane-departure warning but found consumers don't like having a "turn-signal nanny." 

"We are seeing benefits from other systems, but with lane-departure warning, we are not," Kidd said. 

An IIHS study found that two-thirds of drivers turned off the function, which alerts drivers who leave a lane without signaling. By contrast, the study found that less than 1 percent of drivers deactivated forward-collision warning. 

Experts say lane-departure warning alienated consumers in two ways. The system's alerts may irritate drivers, especially if it uses sounds. John Capp, General Motors director of global safety strategy, says consumers like alerts better if "you're not necessarily announcing to your friend in the front seat that "I swerved a little, and I crossed over.'"

GM found that more than half of its drivers turned off its system when it used warning beeps. But when GM switched the warning to vibrations in the driver's seat, two-thirds of drivers kept the system on, Capp said. 

"How we do the [human machine interface] really, really matters," he said. 

But there's another problem. Lane-departure warning is meant to combat a serious danger -- accidents in which a driver runs off the road, often because of sleepiness or intoxication. 

But changing lanes without signaling is common among drivers who aren't drunk or drowsy. Glen De Vos, Delphi Automotive vice president of engineering, notes that "normal drivers do that," so the system winds up sending alerts when no safety problem exists. 

"I think initially with these systems, there were a lot of false positives, and it was irritating," he said. 

Delphi's solution is to add "driver-state sensing," De Vos says, using an in-car camera to determine whether the driver is facing forward and looking at the road. The feature will launch with production vehicles in Europe next year, he said.