Green’s Dictionary of Slang

1. the active, competitive and ruthless world fought over by those of ambition and intent; also attrib.

1978		Parade 16 Apr. 20: Except for her, however, not a single person arrested fit the image usually associated with the superjet, ‘fast-lane’ set.
1989		Kirk & Madsen After The Ball 303: The typical fast-lane gay [...] begins to seek sources of energy and experience that are unhealthy and illegitimate.
1998		C. Fleming High Concept 211: I was just another slug who got caught in the fast lane.
1999		‘Master Pimp’ Pimp’s Rap 190: Pimping and living in the fast lane was me. It’s what I do best.

2. the world of hedonistic pleasures.

2007

N. McCall Them (2008) 25: He liked to soak up stories about wild adventures in the fast lane.