"limit sign was on the motorway, slip-road, or adjacent road so kept on reminding me that I should be doing 30 on the motorway."
And this of course will be one of a multitude of problems that self drive cars would face too - green light says go, oops wrong green light, crunch. Or the graffiti / shaded / unlit / part covered signed means car thinks it's still 70MPH instead of 50MPH oops speeding ticket.
It would probably be better if the car had a satnav or wireless link which inferred the speed limit from the prevailing traffic flow and then used the distance between the car in front and behind to adjust that to the local conditions.
Biting the hand that feeds IT
