The most common and most likely answer to this crossword clue is the 13 letter word BREATHALYSERS
I've seen this crossword clue in The Daily Telegraph
B
R
E
A
T
H
A
L
Y
S
E
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More clues leading to the result BREATHALYSERS
Buddy explains!
The straight part
We know that "drivers may fear these" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case drivers may fear these = breathalysers.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 BREATHALYSERS mean?
BREATHALYSERS noun- A device that measures alcohol in expired air so as to estimate the concentration of alcohol in a person's blood; used by traffic police in cases of suspected driving while under the influence of alcohol.