Satellite navigation systems (satnavs) for cars, in which computer voices announce directions as you drive, save fuel and promote safety  Studies show that, when assigned to novel destinations, drivers using satnavs took, on average, 7 percent fewer miles per journey than drivers using paper maps  Fewer miles driven means, on average, less fuel consumed
Also, the drivers who used satnavs drove more carefully in that they were not taking their eyes off the road to check paper maps
Drivers who are given directions as needed are less likely to change course suddenly or make other risky maneuvers.