But then there's the concern of GPS technology and how inaccurate it is, its like people who rely on using GPS speed over the tacho, they don't realize how inaccurate the GPS device/software can be. Like one of my devices had a bug with hills, The hill is elevating so going 30mph will seem like 15mph in a straight line, a bit of simple maths such as trigonometry would let you work out the speed and distance easily providing the elevation is known, sat nav can see the elevation, I'm doing 50mph but its adamant I'm doing 12mph. Then how many times has the nav device thought you was on a different road? How about the speed errors you also get when going round a bend and changing lane due to the accuracy of the signal?
Unless the insurance industry invest in accurate GPS equipment like surveyors use or GPS technology vastly improves I cant see this happen, which seems like it is extremely unlikely due to the costs involved.