Demonstrating new "infotainment" systems here at the North American International Auto Show, several companies said they will employ mouse-like knobs and buttons, rather than voice interfaces, as a means of accessing electronic features. But with others remaining committed to voice recognition as the interface that best supports the conventional "eyes on the road, hands on the wheel" notion of safety, the interface debate could slow implementation of the in-car PC.

Among those pitching alternative interfaces at the show was BMW, which rolled out iDrive, an infotainment system that's heavy on tactile feel and light on voice technology. The system, to be integrated as a standard feature in BMW's 7 Series later this year, uses a large knob on the vehicle's center console to enable drivers to gain entry to the navigation system, climate controls, telephone and e-mail.

Similarly, Volvo displayed a concept car PC that employs steering-wheel-mounted buttons for input.

And Johnson Controls, a major automotive supplier, demonstrated the Harmony Infotainment Generation 2, which company engineers said uses voice recognition only as an "overlay."

"Voice recognition has its place in automobiles, but it's not a panacea," said David Busch, a senior designer for Johnson Controls (Plymouth, Mich.). "We see it as a complement to methods that use pushbutton controls."

Such philosophies are now part of a growing debate among automotive engineers, many of whom were staunchly committed to voice recognition only three years ago. While some car manufacturers, such as General Motors and Mercedes-Benz, are still betting heavily on voice recognition, others are inching away from it.

"We will use voice recognition to operate the phone," noted Doug Frasher, chief of strategic design at Volvo's California Monitoring and Concept Center (Camarillo, Calif.). "But beyond that, we are going to use voice recognition judiciously because we know there are still problems with it."

Such beliefs fly in the face of the commonly held notion that the only safe auto infotainment systems are those that let users keep "eyes on the road, hands on the wheel." The problem with techniques other than voice recognition, according to this school of thought, is that they require users to divert their attention momentarily from the road.

"There are very few products that have the ability to distract the way an in-car PC does," said Jim Wynalek, vice president and general manager of telematics and multimedia business systems at Visteon Corp. (Dearborn, Mich.). "We don't want people to drive cars and read screens at the same time. That's why we need speech recognition."

Wynalek and many other automotive executives support development of in-car computers that use only tiny displays that fit within the opening used by a conventional car radio. Such displays accommodate only a few words of text.

In contrast, the new tactile systems from BMW, Volvo and Johnson Controls use large, color liquid crystal displays. Such systems are far larger than conventional radio displays: BMW's, for example, measures 3.5 inches high and 9 inches wide, and Johnson Controls' is 7 inches across.

The wide screens work in unison with large console-mounted knobs or steering-wheel-mounted buttons. In essence, the mechanical interfaces use operational techniques similar to those of a PC mouse.

On BMW's iDrive, for example, users can change functions — from communications to climate control, navigation or entertainment — by pushing the console knob forward or back, or side-to-side. By twisting the knob, they can scroll through menus. And by clicking a button located in the middle of the knob, they can select functions.

Similarly, Volvo engineers support an interface that allows users to change functions by pressing a "three-button mouse" on the steering wheel. The system displays menus on a high-mounted, 5-inch by 8-inch screen.

Designers of the new systems emphasize that their products are created from scratch as automotive infotainment systems, rather than fitted aftermarket-style into an existing dashboard opening. More important, the engineers say their systems can be employed intuitively and with a minimum of distraction.

In most cases, they claim, drivers can still concentrate on the road while using the systems' knobs and buttons. Force feedback in the knobs and tactile marks in the handles give each function a distinct feel, so users seldom need to look at the screen. "You can get in this car at night and, never having seen it before, be able to use the radio and the climate control," asserted Hermann Kunzer, a human-machine interface designer for BMW.

Makers of the new tactile systems say their designs are based on extensive user research. They claim that the designs represent an effort to reduce the amount of cognitive loading on the driver, which looms as an important issue as various states consider legislation to prohibit the use of cell phones by drivers while vehicles are under way.

"We had human factors experts and industrial design teams go through these features and determine the easiest way to enable them," said Douglas Campbell, product business manager for infotainment systems at Johnson Controls. "And we found that consumers aren't intimidated by this interface."

Voice of restraint

Developers of the new tactile systems acknowledge, however, that even they will need to tap some level of voice recognition, especially for such functions as e-mail retrieval and Internet access.

"We plan to use speech-to-text and text-to-speech as soon as the proper quality is available," BMW's Kunzer said. "But even then, voice recognition will only be a part of our system. It's not yet reliable enough to be the only medium."

The biggest technical challenge facing voice recognition reliability is noise, engineers said. Noise from the road surface, wind, engine, defroster, fan, radio, windshield wipers, kids in the back seat, pops and cracks in the cabin, and windows opening and closing all conspire to confound speech recognition systems.

Those problems have slowed implementation and acceptance of some in-car PCs. Cadillac's infotainment system has been delayed by more than a year while engineers work on what the automaker has called "technical issues," and Clarion's AutoPC has struggled in the marketplace.

Indeed, only OnStar's Virtual Advisor, a voice-recognition system that employs off-board servers, has reached the market according to plan.

"Speech technology has not come to fruition as quickly as the industry would have hoped," said Paul Hansen, publisher of The Hansen Report on Automotive Electronics. "It's been more problematic than people thought it would be."

Still, many proponents of voice recognition believe that speech technology will ultimately win out. Accuracy, they say, is not as big a problem as voice recognition's detractors have made it out to be.

Most voice recognition makers claim that their existing systems achieve accuracies of greater than 90 percent. Users, they say, balk at voice recognition primarily because they are intimidated by it, not because it's inaccurate.

Voice recognition remains "something that consumers have to get comfortable with," said Wynalek of Visteon, which makes the ICES (information, communication, entertainment and security) system. "The movement toward knobs and buttons is just a transition phase. Once consumers grow comfortable with speech, they won't need the knobs and buttons."

If automakers do lean toward tactile techniques, however, developers of those systems say they won't go away anytime soon. The reason: Systems such as Johnson Control's Harmony Infotainment must be integrated into the dashboard very early in the design process. Unlike voice-based systems, they can't simply be placed in existing car radio slots.

As a result, some tactile systems being explored now will debut four or five model years down the road. And since not every car model is fully redesigned every year, the systems are likely to be in use for some time after that.

"There's no doubt that speech recognition is the future," said Dan Garretson, automotive analyst for Forrester Research (Cambridge, Mass.). "But even when speech technology is ready, you're never going to get away from those tactile techniques. Some users will always prefer them."