@0xZoom mine does similar things regularly. On exiting the Lane Cove tunnel northwestbound, it picks up the 70 sign on the side road. On entering the Harbour Bridge southbound on the Warringah freeway, it picks up the 40 sign from the bus lane of the Cahill expressway. And yes, it still picks up the bloody 40 signs on the backs of buses, whether they're stationary or whether I'm driving behind them.
@Skurfer The problem with training the AP on other driver behaviour is it replicates their crappy driving in my car. That's a highly undesirable outcome. AP still needs to detect speed limits, as those will change more quickly than the training set for AP gets updated. Think roadworks, time variable speed limits, and congestion - you don't want the car to slow down in free flowing traffic because it detected a slowdown there some months back.
And woe thee if they start replicating my favourite "other drivers are morons" behaviour: slowing down on the freeway when entering a tunnel. It's the same width, same visibility, same everything, it just *feels* tighter. The fact that 99% of the driving human population is unable to a) question themselves "why do I slow down now?" and then come to the logical conclusion "whoa, I don't need to, the road parameters are all the same" clearly means we're headed towards extinction at the speed of an impacting celestial bolide.
And then lastly,
@JonDarian, calibrating the speedo from GPS is problematic. Contrary to popular belief, consumer grade GPS is actually not all that resilient, and thus not really suitable for such a critical function as calibrating your speedo. When all parameters are OK (which is true 90% of the time) *and* you are on a flat and straight surface, that would certainly work and the accuracy is good enough. But there's a significantly non zero chance that the GPS is somewhat inaccurate or the road you're on isn't straight and level enough to make this a resilient calibration.
