“There’s a general trend towards the completely self-driving car,” said Csaba Csere, an engineer and the editor of Car and Driver magazine. He said it had once been assumed that such cars would have to be guided by technologies built into roads, an unfeasibly expensive proposition.

“Now we have cars with G.P.S.,” he said, referring to global positioning satellite systems. “Combine that with radar cruise control, add a lane-changing system and throw in a transponder, or cameras, and pretty soon you could have a car that self-drives itself in the middle of a bunch of conventional cars.”

Many executives and researchers say they have no such end in mind. Certainly, there are headaches to ponder. Like, what will lawyers do if self-driving cars get in accidents?

“I think it would be very risky for an auto company to take its eye off of the fun of driving, but where it can lead is to having a more enjoyable driving experience and a safer one,” said Larry Burns, G.M.’s research and development chief.

He drives a Cadillac XLR, a sports car that is among many new luxury vehicles equipped with “adaptive” cruise control, which can slow a car drastically if another swerves in its path. The next-generation technology, expected within one to two years, will actually stop cars in traffic.

General Motors and other companies are also developing transponders that can communicate with other cars to create on-board traffic-snarl warning systems.

More here.