The most common and most likely answer to this crossword clue is the 7 letter word FLYOVER
I've seen this crossword clue in The Sunday Telegraph
F
L
Y
O
V
E
R
Buddy explains!

The straight part
We know that "bridge" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case bridge = flyover.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 FLYOVER mean?
FLYOVER noun- A low-level flight, especially of military aircraft, of a ceremonial nature; a flypast (British).
- A road or railway that passes over another, allowing routes to cross without interruption.
- A high-level overpass built above main overpass lanes.