Car to avoid on the motorway, initially (6)
I believe the answer is:
'car' is the definition.
(I've seen this before)
'avoid on the motorway initially' is the wordplay.
'avoid' becomes 'dodge' (dodging is a kind of avoiding).
'on' means one lot of letters go next to another.
'initially' says to take the initial letters.
The initial letter of 'motorway' is 'm'.
'to' is the link.
(Other definitions for dodgem that I've seen before include "Small car at funfair for bumping into others", "Fairground amusement vehicle", "ride - with 14a", "Electric car", "Car used in fairground".)