Change lanes erratically (5)
I believe the answer is:
weave
'change lanes erratically' is the definition.
(I've seen this in another clue)
This is all the clue.
(Other definitions for weave that I've seen before include "Interlace strands of material" , "Make material" , "Make (fabrics)" , "Make (basketwork)" , "Combine into a whole" .)