Carmakers are spending more on silicon these days, as electronics and software spread throughout motor vehicles, from underhood control units to driver information systems and rear-seat entertainment modules. It is now estimated that the cost of the electronics in a new car rises by 9-16 percent each year. In the 2001 model year, electronics accounted for 19 percent of a mid-sized vehicle's cost. In the year 2005, it may be 25 percent for mid-sized cars and possibly 50 percent for luxury models.

So in addition to being pervasive, automotive electronics had better be reliable. The failure of a 10-cent part can ruin a US $30 000 car purchase. Failures in braking and steering can cause injury or death. Servicing a system buried deep within a car is costly. And designers of automotive systems must be prepared for users who give the product almost zero maintenance. "It's not like aviation or aerospace, where you have human eyes looking at it after every few hours of operation," said Patrick Lincoln, director of the Computer Science Laboratory at SRI International (Menlo Park, Calif.). Now, in fact, the shoe is on the other foot, with aircraft makers eyeing mass-produced automotive databuses and other advanced technologies for possible avionics use.

Reliability can't be an afterthought, especially in the hostile underhood environment. Its foundations are laid early in the design process, through improved communications between manufacturers and suppliers and the use of formal development tools. And the quest for reliability (and testability) persists throughout the supply chain, from device manufacturers and system integrators to the vehicle makers themselves. Further, many of the innovations that make the vehicle electronics revolution possible are also enhancing repair service once vehicles leave the showroom