Illuminated the sides of the motorway, but with restriction (5)
I believe the answer is:
limit
'restriction' is the definition.
(I've seen this before)
'illuminated the sides of the motorway but' is the wordplay.
I cannot quite understand how this works, but
'the' could be 't' (the is pronounced as a 't' sound in some dialects) and 't' is found in the answer.
'motorway' could be 'mi' (resembles M1, English motorway) and 'mi' is located in the answer.
The remaining letters 'li' is a valid word which might be clued in a way I don't understand.
This may be the basis of the clue (or it may be nonsense).
'with' is the link.
Can you help me to learn more?
(Other definitions for limit that I've seen before include "Furthest extent" , "Ceiling" , "Confine within bounds" , "Extreme point" , "As far as something can go" .)