Comment Seems more complex than necessary (Score 1) 51
...reducing speed to 30mph because the camera has picked up a sign in a side street while driving past...
Are you sure it reads road signs? That seems vastly more complicated and much less reliable than simply getting the speed limits using GPS coordinates and a map. Every car I've driven that has a speed limit display seems to use this approach and while it does mean that you have to keep the maps up to date I'd think that would still be much more reliable that reading road signs for reasons similar to what you mention. In fact, you will have to use GPS to know how to interpret the signs: Canadian speed limit signs are almost identical in appearance to US signs but the units are km/h, the same applies between UK vs. EU signs which are identical and neither includes units. So if you have to have a GPS map to know how to read the signs why not just use it to get the limits too?