Travel fast in a car (5)
I believe the answer is:
motor
This might be a double definition.
'travel fast' is the first definition.
'motor' can be an answer for 'travel' (motoring is a kind of travelling). I am unsure of the 'fast' bit.
'car' is the second definition.
(motor can informally mean a car)
'in a' acts as a link.
Can you help me to learn more?
(Other definitions for motor that I've seen before include "Engine of vehicle" , "Car; powered machine" , "Move quickly" , "Driver" , "Wheels" .)