Looking at his site he has them under the long exposure category.
If he did the zoom/focus during exposure, would the vertical trails not have a similar effect? On some of the pics in his portfolio the launch streaks (tracer, whatever you call it) look like a long exposure shot vs zoom during exposure.
Then again I'm certainly no expert.
http://www.daveyjphoto.com/tagged/long-exposure
I don't prefer them over regular shots myself, but I thought it was a very neat technique.