[tweetiepooh]

My car (2016 Mondeo) has a system to read speed limit signs. The TomTom SatNav (5200) can know about road speed limits including reduced for road works and for average speed zones will display my average speed. Neither are 100% accurate though, the former can read the wrong sign sometimes or if joining from lay-by or some side roads where there isn't a sign assumes speed from map data (map is very out of date on in car system). The latter relies on a mobile signal and have up to date information being transmitted but does get it right most of the time.


Here is a question though, you are driving along nicely at the limit but some buffoon in an older car is tail gating you quite merrily. You car "detects" a new lower limit and slows down... Will it detect said buffoon and slow appropriately, will you have time to override to slow appropriately?


Another - I've seen some situations with a lower limit sign but notice that only applies during certain times or situations or when lights are flashing.


I think there are just too many variables and while some system to warn of speed (like what my car does) seems sensible to have that system exert control of the car simply based on correct reading of road signs or GPS data is far less so. My TomTom includes lifetime map updates and has mobile chip to get new information on traffic etc, my car doesn't and I don't want and can't afford to have to buy new maps all the time. Who pays for that infrastructure? Oh we will of course.