Drivers have depended on gestures to maneuver through traffic since the dawn of the auto age, from a friendly wave to a shaking fist -- or worse.
Now, automakers are starting to use gestures to let drivers control car functions, whether it's an approaching hand to activate a dashboard infotainment system or the kick of a leg to open a crossover's tailgate.
Not only are the latest gesture technologies on display this week at the International CES here, but more will be featured at the North American International Auto Show in Detroit next week.
Hyundai plans to introduce a sleek concept car that incorporates "3-D gesture" control so a driver can operate an audio system with the wave of a hand.
The goal: Make it "safe and easy to use," says Mitchell Zarders, a Hyundai senior engineer, who notes the functionality is still in its infancy. "You are going to be amazed in a couple years. (Gesture control) isn't going to resemble anything that you see today."
As with so many promising technologies, interest in the use of gestures to make things happen inside and outside cars isn't so much the product of a breakthrough as it is a confluence of events.
First is safety. Designers are striving to find ways that drivers can avoid fiddling for buttons, knobs or icons on an electronic display screen as a car barrels down the road at 70 miles an hour. The use of voice commands to change radio stations, phone home or search for an address is becoming common. The ability to wave a hand, rather than having to glance at the dashboard, is considered a natural next step in the war against driver distraction.
Three of four consumers said safety is the top consideration in buying a car, according to a survey of 2,100 people released this week by auto parts supplier Johnson Controls. Safe operation of systems is considered critical.
Consumers have already seen the potential for motion sensors and gesture control in other aspects of their lives, whether it's outside floodlights that automatically illuminate when a critter prowls the backyard or playing group-oriented video games.
From mock bowling to disco dance contests, millions of players have discovered how video games monitor and mimic their body motions using systems such as Microsoft's hands-free, body-sensing Kinect controller for the Xbox 360, Sony PlayStation Move or Nintendo Wii remotes.
"Three-year-olds are touching the TV, expecting it to move," says Parrish Hanna, global director of human-machine interface programs for Ford Motor. "Between consumer electronics and automotive, there is going to be a constant struggle" for higher levels of technology, including gesture control.
Car buyers have come to expect the same wizardry in vehicles as they find in consumer products at home. New cars are being loaded with sensors and cameras. Using radar, they can parallel park themselves or hold their place in stop-and-go traffic. Even driverless cars, shown at the consumer electronics show this week, are on the horizon with the help of laser-ranging systems.
Here's how gesture technology is showing up in cars.
Drowsy driver detection. Lexus has mounted an infrared camera to steering columns of 2013 GS and LS luxury sedans that "maps" drivers' faces, searching for signs they're looking away from the road or falling asleep.
The system works in conjunction with the car's radar to detect another vehicle or object that could mean a crash is imminent. Then, the car automatically brakes and cinches the seat belts to prepare for a collision.
Using gesture recognition means the system "will activate a tenth or a hundredth of a second earlier" than radar alone. General Motors and other automakers are researching similar driver-monitoring systems. "We are watching the head," not just the eyes, "and checking to see if there is tilting," to indicate drowsiness, says GM engineer Mike Hichme.
Opening doors. Moms, dads or shoppers can wave ankles under the tailgate of a Ford Escape or C-Max family hauler to get it to open when their arms are filled. Sensors underneath the bumper detect the leg motion.
Ford is looking at the possibility of sun roofs that open or close at a gesture. It makes more sense than voice commands, Ford's Hanna says. "You don't naturally say 'sun roof.' But you will naturally reach for something.
"If I have got my hands full and I'm trying to open a door, and I'm leaning into the door and trying to gesture (for it to open), those type of things are natural," he says. "We are going to be extremely simple. And if you have to take your eyes off the road, it's a failure."
Infotainment systems. If a driver moves his or her right hand within 8 inches of the center touch-screen of a Cadillac equipped with the CUE infotainment system, the screen illuminates and displays icons for more features.
CUE, for Cadillac User Experience, can be found on the ATS and XTS sedans and the SRX crossover and will be coming to the rest of the lineup, says engineer Mike Hichme, who helped develop the system.
But systems such as CUE can be controversial. Consumer Reports blasted CUE in a blog posting as potentially causing more driver distraction. Because the screen doesn't brighten until your hand gets close, it might be harder to zero in on a particular icon from among many.
Asked this week about gesture technology in a meeting with reporters at the Motor Press Guild in Los Angeles, David Strickland, administrator of the National Highway Traffic Safety Administration, says he's aware of Cadillac's system but hasn't seen enough yet to weigh in with an opinion. But he says the agency generally supports new systems that "keep hands on wheel, eyes on road."
With that in mind, Hyundai demonstrated its "3-D gesture" system, a version of which will appear on the HCD-14 concept, which is meant to hint at the future design direction for Hyundai's midsize luxury sedan.
The system shown at CES allows users to control air conditioning settings or displays on the instrument clusters with an open palm hovering in the air. For the air conditioning, a pushing motion takes the driver through different choices for fan settings, as seen on the console screen.
The HCD-14 will have a more sophisticated setup. It will work in a similar way but allow for control of more functions, and it can be used in conjunction with a heads-up display so the driver doesn't have to look down at a dashboard. Settings, as chosen with hand gesture, appear to float above the dashboard.
The system is "much easier than reaching all the way across, taking your eye off the road," Zarders says.
As is often the case, aftermarket auto purveyors have their own products. Consumer electronics maker Monster offers its own system to let drivers pick music from Apple iPods or iPads, connected by cable in the car, with a hand wave.
The iMotion CarPlay Direct Connect 3000, which went on sale in May for about $120, plugs into both the car's power port, formerly called the cigarette lighter, and the music device. When a driver's hand swipes from left to right about 2 inches from the infrared light on the device, it advances to the next song.
"Let your hands do all the music finding," says Liz Thomas, a mobile products manager for Monster. "It's for that distracted driver. You don't want to have to pick up the device and look at it."
As more gesture-based products emerge, the technology will get even better. Though the systems detect hand movements now, improved cameras could mean they could even detect individual fingers, opening the door to more applications, says Benson Tao, product marketing manager for Vivante, a Silicon Valley firm that's been talking to automakers about gesture technology appli-cations.
When a finger starts moving toward a dashboard, future cars could use gesture technology to deduce where it's going and try to help the driver by presenting a more simplified display based on the expected action, says Loick Griselain, vice president of driver information products for Johnson Controls. For instance, if a driver reaches out to turn up the heat in the car's cabin, the electronic button could be made to suddenly appear larger as the hand approaches, making the task easier.
Not only hand and foot movements are being detected, but a head nod could be used to operate controls in future cars, Griselain says. With the dip of a noggin, map information or fuel-use data could be passed back and forth between the screen on the car's center console to the display screens around the speedometer.
With that kind of potential for gesture control, the ideas are flowing: a seat massage unit that could be activated by a gesture; a virtual emergency brake for parents who sit nervously in the front passenger seat, teaching their teens to drive; turning or advancing a DVD playing on the infotainment system in the back seat.
The potential for gesture technology in cars is important, says Eisuke Tsuyuzaki, chief technology officer for Panasonic, a big maker of automotive display screens. "We have got a lot of people behind it."