Once the stuff of science fiction and cartoons, automakers are racing to be first with vehicles that drive themselves. While the first systems won’t be that ambitious — don’t expect to work crossword puzzles while lounging Jetsons-style behind the wheel — they point to future cars that will make driving easier and actively avoid accidents. The latest to disclose plans is Ford Motor, which is developing a feature for heavy traffic jams that would let the car keep up with traffic and stay in its lane. For now, Ford will only say that "Traffic Jam Assist" will be available in the "mid term," meaning at least five years away.