The most common and most likely answer to this crossword clue is the 7 letter word HAULAGE
I've seen this crossword clue in The Guardian
H
A
U
L
A
G
E
More clues leading to the result HAULAGE
Buddy explains!

The straight part
We know that "Transport" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case transport = haulage.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 HAULAGE mean?
HAULAGE noun- The act of hauling.
- The business of transporting goods.
- The charge levied for hauling or pulling a ship or boat.