Putting wire on a motorway is friendly (8)
I believe the answer is:
amicable
'is friendly' is the definition.
(associated in meaning)
'putting wire on a motorway' is the wordplay.
'putting wire' becomes 'cable' (I am not sure about this - if you are sure you should give a lot more credence to this answer).
'on' is a charade indicator (letters next to each other).
'motorway' becomes 'MI' (resembles Mc, English motorway).
'a'+'mi'='ami'
'cable' put after 'ami' is 'AMICABLE'.
Can you help me to learn more?
(Other definitions for amicable that I've seen before include "Friendly, peaceful" , "warm" , "Friendly and sociable" , "Friendly, reasonable" , "Male cab I change to, just to be friendly" .)