The most common and most likely answer to this crossword clue is the 7 letter word FREEWAY
I've seen this crossword clue in The Times
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More clues leading to the result FREEWAY
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The straight part
We know that "road in US" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case road in us = freeway.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 FREEWAY mean?
FREEWAY noun- A road designed for safe, high-speed operation of motor vehicles through the elimination of at-grade intersections, usually divided and having at least two lanes in each direction; a dual carriageway with no at-grade crossings, a motorway.
- A toll-free highway.