Taking you for a ride: the world's car makers race to develop safe self-driving vehicles

At the recent Frankfurt Auto Show, Ford Motor Co unveiled a new feature that lets drivers pre-set their car to go at or just above the speed limit. In-car cameras and software read and react to road signs, speeding the car up or slowing it down.
Ford’s Active Speed Limiter system is available on select models in Europe, but not, ironically, in the United States, the carmaker’s home market, where road signs come in different shapes and sizes, and are often obscured by shrubbery.
So it goes on the road to the self-driving, or autonomous, car -- a journey of, well, stops and starts that most experts say will take a couple decades to complete.
Meantime, advances in "semi-autonomy" -- features that help handle tricky or tiresome driving situations but still require a driver’s oversight -- have sparked a high-tech automotive arms race, with car companies vying to launch the most advanced features.
Automakers hope semi-autonomous features will, over time, help drivers and regulators get over fears of riding in vehicles that accelerate, steer and stop themselves, making potentially life-or-death judgements.