Road tester crashing (6)
I believe the answer is:
street
'road' is the definition.
(street is a kind of road)
'tester crashing' is the wordplay.
'crashing' indicates an anagram.
'tester' anagrammed gives 'STREET'.
(Other definitions for street that I've seen before include "Tester (anag.)" , "A thoroughfare or public road" , "Roadway" , "Way; setter (anag.)" , "Paved road" .)