Open-top car seen in roll without notice (8)
I believe the answer is:
Here is my best explanation:
'open-top car' is the definition.
(I've seen this before)
'roll without notice' is the wordplay.
'roll' becomes 'roster' ('roster' can be a synonym of 'roll'**).
'without' means one lot of letters goes inside another ('without' can be similar in meaning to 'outside').
'notice' becomes 'ad'.
'roster' going around 'ad' is 'ROADSTER'.
'seen in' is the link.
(Other definitions for roadster that I've seen before include "Open two-seater car", "sporty vehicle", "Old car", "Small open-top car", "sporty car", "Open-top car", "An open car without rear seats" and "Open-topped car".)