Ford says it\'s working on a system that will practically automate driving in traffic jams and allow drivers to relax when stuck in stop-and-go situations. The Traffic Jam Assist system, still in the experimental stage, uses sonar sensors and cameras to determine the speed of cars in front of the driver and to monitor lane stripes on the road. The sensors will tell the car how fast to go to match the speed of the driver in front while the cameras will warn drivers if they start drifting out of their lanes, Ford engineers said. \"Drivers spend more than 30 percent of their time in heavy traffic,\" engineer Joseph Urhahne said in a statement. \"Traffic Jam Assist could help make traveling through congestion a more relaxing experience and, by keeping pace with the flow of traffic, potentially help relieve road congestion.\" One study suggested if a quarter of cars on the road had follow-the-leader systems like Traffic Jam Assist, congestion could be cut by more than a third in major cities, The (Cleveland) Plain Dealer reported. Ford hasn\'t announced if or when it would put such as system in future cars, the newspaper said.