The most common and most likely answer to this crossword clue is the 4 plus 8 letter word HARD SHOULDER
I've seen this crossword clue in The Guardian
H
A
R
D
S
H
O
U
L
D
E
R
More clues leading to the result HARD SHOULDER
- Tough joint of meat for refuge, by the way
- It's difficult to accept this can accommodate broken-down motorway vehicle
- Tough cut of meat — that's by the way
- Difficult joint? By the way it is!
- Carry with difficulty from edge of motorway
- Demanding push to create space for emergency stops
- Edge along road, closely pursued by bear
- Ought in more difficult circumstances to stop here
- Part of road that’s difficult to bear?
- Tougher outside, ought to stop here by the road?
Buddy explains!

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.