Song is all improvisation - keys, sax, & bass. Seemed too laid back & riff(with variations) oriented to put in smooth jazz. But it is definitely smooth.
Story behind the song
Growing up in Houston, I didn't usually care much for it. But I always found the buildings and lights downtown beautiful wrapped in the soft blurs of night time fog. This song is about the feeling cruising around in the city fog in the post midnight hours.