It's a tenor feature built on a hemiola-like melody-rhythm. The influence Bob Mintzer's writing comes through a bit in this piece.
By the way, Metroliner will be published in early 2016. As for right now, UMD Jazz gets dibs on it.
This was what I refer to as a blank score commission in which my assignment was write whatever you please. I was told that there'd be a strong rhythm section and tenor soloist, so that certainly gave me some guidance. And I've heard the band before—they're excellent—so I knew the ensemble would be able to handle whatever I throw their way.
Anyhow, here are the score and Finale playback file if you'd like to check them out.