I like the deceptive simplicity in this haiku, Andrew. I say deceptive because it only looks simple. There are tiers of meaning and your poem allows for more than one interpretation by it's "not telling all".
A beautiful modern haiku. There seems to be something intimate and personal the flitting butterfly conveys to everybody concerned. The "butterfly" kigo and the well-defined kireji after "motorway jam" bring in a silent eloquence with the verb "flits".Great Thanks Andrew.
Well done.