speeding in passing lane

The other day I was driving to the mall. I went down a road in the
rightmost lane. When I was approaching the intersection, I started
signalling, checked my mirror, and there was a big pickup off to the left.
Well, I thought this guy, being a bit over the speed limit would GET A CLUE
and slow down, but he wouldn't. In fact, he seemed to speed up some. This
lasted a few seconds, and then I gave up. So I ended up having to turn
left into a grocery store and cut across the intersection without being able
to just do a left turn.