The most common and most likely answer to this crossword clue is the 8 letter word METALLED
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Buddy explains!
The straight part
We know that "Suitable for regular traffic?" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case suitable for regular traffic? = metalled.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 METALLED mean?
METALLED verb- To make a road using crushed rock, stones etc.
- (of a road) Surfaced, tarred, covered in stone or crushed rock (usually tar-coated).
- (of any object) Made of metal or having metal fittings or plating.