Heavy vehicle (11)
I believe the answer is:
steamroller
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">heavy vehicle</span>' is the definition.<br/ ><span class="explanation-format__explanation">(I've seen this before)</span><br/ ><br/ >This is the entire clue.<br/ ></span>
(Other definitions for steamroller that I've seen before include "slow vehicle" , "Heavy vehicle" , "Forcibly crush" , "Knock flat" .)