Are our cars getting too complex?

With all of the recalls plaguing Toyota and other companies, the question of electronics and software are suspect in a few of them.

Andy Chou, a chief scientist at Coverity says that despite the best efforts of coders and reviewers, most professionally written software programs still have about one bug per thousand lines of code. Coverity is a software integrity company that is the trusted standard for companies that have a zero tolerance policy for software failures and defects. They analyze software for defects and counts among its customers automobile-parts manufacturers such as Bosh, and car manufacturers such as Daimler and Renault.

Citing a widely used figure, Chou said that the average luxury automobile has more than 100 million lines of code, spread across all of its microcontrol units.

This would mean that the auto has twice the amount of code found in a desktop operating system.

And, in many cases, this code could have been developed under the severe time pressure of getting new models out each calendar year.

As this collection of software grows more complex, there may be more errors that are more difficult to find, or even reproduce.

For instance, one of the challenges investigators have had is in reproducing a sudden acceleration problem in test labs. This could be due to some sort condition in which a system may behave differently from one moment to the next depending on the largely indeterminate timing of certain interrelated events, Chou said.

Also, as different control units of the automobile are networked together, such as engine control, transmission control, antilock brakes, etc. as manufacturers are increasing doing then the ways errors can spring up, grow even larger still, Chou said.

"We're talking about very large, complex systems," Chou said. "When these systems are connected, they can start to have behaviors that are emergent. They are not necessarily behaviors that they would have on their own but you put them together, they may do things that are unexpected."




 

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