Green’s Dictionary of Slang

(US Und.) a converted Greyhound bus, painted grey, that is used for transporting prisoners securely between jails, courts etc.

1976		M. Braly False Starts 328: Again I rode the gray goose to Quentin.
1990		S. Morgan Homeboy 182: ‘This Gray Goose stops at Quentin, Soledad and Coldwater, Barker,’ said Oblivia, shaking her chains at the idling bus.
1993		Snoop Doggy Dogg ‘Murder Was the Case’ 🎵 No more indo, gin and juice / I’m on my way to Chino, rollin on the Gray Goose.
1998		www.yesmagazine.org Summer 🌐 After they are convicted, inmates come to prison on the bus from the county jail. The inmates call the bus ‘The Gray Goose,’ because at one time these buses were all gray and always migrating from one prison to another.
2005		Moussie ‘Northside Soldier’ 🎵 Rollin up San Quentin C.D.C reception / [...] / He‘s on a gray goose hunt to his first joint.
2011		D. Barragan Nuestra Familia 41: Casper and I were chained, handcuffed, and placed in the front cage of the gray goose headed for [...] ‘Gladiator School’.