UK Road colours are not correct.
The country that I lived in, as well as Ireland do not have the right road colour scheme that is widely and so widely used.
The right colours are:
Motorways: Blue
Primary A-Roads: Green
Other A-Roads: Red
Secondary B-Roads: Orange
You should also be aware of a emerging issue regarding UK road colours on Google as well. It can be found at https://productforums.google.com/forum/#!category-topic/maps/maps/8eGGn3Vd75Q
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