The most common and most likely answer to this crossword clue is the 9 letter word RUNABOUTS
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More clues leading to the result RUNABOUTS
Buddy explains!

The straight part
We know that "cars" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case cars = runabouts.The cryptic/wordplay part
In cryptic crossword there's often an wordplay/cryptic part as well.This part involves a more complex hint, such as an anagram, homophone, hidden word, etc.
Sadly, We don't have an explanation for this specific crossword clue yet.
What does RUNABOUTS mean?
RUNABOUTS noun- Any of several small vehicles, especially a small motor car for use on short journeys.
- A motor car having a single row of seats.
- A light, open, American horse-drawn vehicle with four large wheels.
- A gadabout or vagabond.