Industry analysts said this week that too many companies now bring in human-factors experts as an afterthought, leaving the bulk of the design work to C programmers and electronics engineers who have a far higher comfort level with complex systems than the average consumer does. Experts warn that failing to consider the user interface at the outset could result in systems that compromise the safety of drivers and passengers.

"People can cope with a lot of distractions," said Phil Spelt, a senior research scientist at Oak Ridge National Laboratory, which is conducting a study on driver distraction for the U.S. Department of Transportation. "But all it takes is one split second when they can't cope, and you have a major accident."

To deal with that potential problem, a growing number of automakers and vendors are adopting design techniques intended to create simpler, more intuitive user interfaces. By employing rapid-prototyping software that automatically generates code for graphical user interfaces, some engineering teams are building and debugging prototypes more quickly. As a result, they say, they're also bringing human-factors experts into the design process earlier.

"Simulation models allow customers to see how the system works and to do usability and ergonomics studies," said Peter Abowd, supervisor in advanced interiors for Visteon Corp. (Dearborn, Mich.), which employs rapid-prototyping tools and tests new designs in a vehicle simulation lab. "So you can have software engineers, human-factors engineers and product designers all working together."

But most product developers still prefer to write their own code, especially logic-related code, experts said. The small memories and relatively low performance of embedded microcontrollers call for a deft programming touch, and many developers therefore hesitate to delegate that task to a software program. As a result, many product manufacturers are still leaving user interfaces in the hands of logic programmers, experts claim.

Time constraint

Ironically, heavy demand for infotainment products may be one of the biggest causes of such design problems, experts said. As automakers strive to bring those products to market faster, many revert to tried-and-true design techniques. The problem is, such techniques are less likely to be successful as electronic features grow in complexity.

"Take a look at the products out there today, and you'll find features that are buried, difficult to use and unclear," said Douglas Campbell, product business manager of infotainment systems for automotive supplier Johnson Controls Inc. (Plymouth, Mich.). "Too often, the people who are designing these systems don't understand the bigger picture." As a result, many radios and navigation systems present a confusing array of buttons that are tough for consumers to navigate without frequently consulting the user manual.

Up to now, the design process has been the culprit in the creation of lackluster user interfaces, industry experts said. Time constraints and the growing importance of software have placed such interfaces into the hands of programmers. Often, those programmers are the same people who write code for engine and transmission controllers. "Too often, the device gets designed and assessed, and then they call in the human-factors department to bless it," said Spelt of Oak Ridge National Laboratory. "But human factors should be involved in the conceptual stage of the design, not after the fact."

When human-factors experts get called in late, substantial changes are often impossible. Manufacturing engineers may already have begun tooling up, and deadlines have drawn too close, Spelt said.

Further, C programmers are not always well-suited to the task of designing an interface. "Software developers have a very different mindset than the average consumer," said Michael Slater, chief technology officer for Phototablet Inc. (Santa Rosa, Calif.). "By necessity, they are people who are able to keep a great deal of detail in their heads. They're capable of dealing with a lot of complexity, and that makes them fundamentally unsuited to judge whether an interface will work well for the average consumer. Concepts that seem perfectly reasonable to them are not going to work well for consumers."

Changing the process

Product design engineers say the solution to the problem is to put the design in the hands of a graphics designer from the outset. Graphics designers, who typically have experience in art and layout, then consult with human-factors experts to find a simple, intuitive design for users.

That's what engineers at Johnson Controls did in the recent design of the Harmony Infotainment Generation 2 system, which rolled out in January. Johnson first assembled a cross-functional team that included mechanical and electrical engineers, industrial and graphical designers, and human-factors experts. The team employed rapid-prototyping software to do an initial benchtop simulation on a laptop computer. Using a so-called fail-fast approach, designers debugged the system before taking it to a full-fledged driving simulator and testing it again in a limited hardware setting.

Engineers say one key to such efforts is the availability of rapid-prototyping software, which allows graphical designers and human factors experts to get involved earlier in the process. Until recently, programmers were needed to handwrite the code for the graphical user interface (GUI). Typically, they created the display on the basis of hand sketches. Human-factors experts then stepped in after the GUI was finished.

Today, programs such as Altia Design, from Altia Inc. (Colorado Springs, Colo.), provide an environment in which a non-programmer can build a user interface. A complementary program known as DeepScreen, also from Altia, takes that graphical interface and automatically generates deployable C code that can be used in logic and control software.

DeepScreen is compatible with so-called state tools, such as BetterState, from Wind River Systems Inc. (Alameda, Calif.); Statemate, from I-Logix (Andover, Mass.); and visualState, from IAR Systems. It is also compatible with such Unified Modeling Language (UML) programs as Rational Rose, from Rational Software Corp. (Cupertino, Calif.); Real-time Studio Professional, from Artisan Software Tools Inc.; and Rhapsody, from I-Logix.

Similarly, at least two companies — Virtual Prototypes (Montreal) and e-SIM Ltd. — offer software programs that combine code-generation capabilities for graphical interfaces and for logic.

Such programs may provide the impetus to pry engineering teams away from the time-honored technique of handwriting the graphics code for user interfaces and for the logic associated with them. It's estimated that approximately 80 percent of user interfaces still use handwritten code. "Handwritten code has always been the leader, because the requirements of embedded systems are so tight," said Altia president Mike Juran. "Embedded systems have small memories and low-performance microprocessors, so you really have to hand-massage the code to get it to work."

For that reason, some users say they prefer to separate graphical code-generating capability and logic generation. "You can use software tools to draw graphics for a very simple product or a very complicated one," said Abowd of Visteon. "But logic code is another matter. The behavior of the product depends on good code."

Juran nonetheless believes that the trend will swing toward use of code-generating programs, especially for graphical displays. "The logic portion of the code is still very much an art, and auto-code usually won't perform as well as handwritten code in that area," he said. "But the graphics portion of the code is very straightforward. There's no reason it can't perform as well as handwritten code."

Automotive companies say they are using such programs to develop complex user interfaces for radios, audio systems, climate controls and telematics units. "The software lets us build behavioral models that we can test in a virtual environment," said Abowd of Visteon. Visteon and other companies now test models in "caves" (computer-automated virtual environments) and in vehicle simulators costing millions of dollars.

Automotive engineers say the products enable them not only to improve the quality of their displays but also to cut weeks from development time.

The same techniques are being applied in aerospace, for cockpits and heads-up displays, as well as in consumer electronics and major appliances, such as washing machines and refrigerators, which are starting to incorporate complex user interfaces.

In the process, experts hope that such techniques will enable human factors engineers to make automotive products safer. "If a product is going to affect safety, then someone with a knowledge of human factors should be involved in the design from the start," said Spelt of Oak Ridge National Laboratory. "And that almost never happens now."