If my car could read speed signs and adjust its maximum speed automatically, I would constantly be harangued buy other drivers in my area.
I live in a 20mph zone not that you would no it from the speed many vehicles travel at), and when I leave to go to my local town, I pass a sign which tells me I'm entering a 30mph area which is only 12meters from a traffic island on a main road which is limited to 40mph, but there is no 40mph sign at my point or access. When I leave the island to go to my local town, the road is limited to also limited to 40mph, so there is no speed sign on the exit of the island
This means the only speed sign my car would see is a 30mph sign which it would follow until it saw the next speed limit sign which is also 30mph as I enter the outskirts of the town about a mile away.
There must be plenty of other similar situations around the country.
leaving the 20mph zone but it doesn't tell me what the speed limit is beyond the sign.
The other very unclear situation that seems to be coming far more common is when road works are started and in four locations within 5 miles of me, a reduced speed limit has been applied becasue of road works or for slow moving site access. The contractors have posted the normal temporary A frame signs with a conforming lower speed limit sign, but they have only spray painted the official higher speed limit signs, and in many instances, the sprayed paint is so thin you can still clearly see the original higher speed limit. They also don't have "End of road work" signage, so its unclear when the original limit is reapplied. Very confusing.
In one particular location the speed limit has been dropped from 50 to 40mph, and just after the site entrance an A frame board set up about 30 metres in front of an original sign, which looks as though its allowing the speed to increase, this is reinforced by the fact there is a 50mph, symbol painted on the road surface which is still totally visible, yet a couple of hundred metres further up the road is another A frame 40 mph sign. Why don't these contractors have a drawstring bag to fully cover the original signs to avoid this confusion?