GPS by itself isn't accurate enough to determine what lane you're in. Even WAAS GPS [1] (used by autopilots for airplanes) is specified to be accurate only up

GPS by itself isn't accurate enough to determine what lane you're in. Even WAAS GPS [1] (used by autopilots for airplanes) is specified to be accurate only up to 25 ft, although the measured accuracy is usually around 3 ft. [1] https://en.wikipedia.org/wiki/Wide_Area_Augmentation_System https://en.wikipedia.org/wiki/Wide_Area_Augmentation_System