The most common and most likely answer to this crossword clue is the 11 letter word DOUBLE-PARK
I've seen this crossword clue in Independent
D
O
U
B
L
E
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P
A
R
K
Buddy explains!
The straight part
We know that "help to block the road" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case help to block the road = double-park.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 DOUBLE-PARK mean?
DOUBLE-PARK verb- To park a car next to a car already parked on the side of a street, obstructing traffic.