[RoundelM3]

So if "tire wear" were to have an effect on a GPS unit's accuracy, how does one account for using a portable GPS in "walking mode"? Will it's accuracy depend on shoe size, sole thickness, stride differences, etc.? Since my Garmin units aren't connected to any of my car's instrumentation, there's no way that miniscule differences in tire size will affect its accuracy.

That said, why would the Ultimate Driving Machine need this GPS-adaptive technology? Isn't that what us drivers are for? Maybe it'd be good for those who view automobiles as "transportation appliances" and would rather let the car drive itself, but not for me.