A law enforcement vehicle, specifically a cruiser or highway patrol car. From the shape of the old-style revolving lights that resemble old gumball vending machines. CB jargon.
Got a bubblegum machine knockin' on your back door (there is a cop car on your tail)
by Dr. Badwrench November 26, 2006
A Highway Patrol Officer, derived from when the siren on a HP car was a single strobe and looked like a bubble gum machine.
Looks like the bubble gum machine done hit the jackpot (He pulled someone over).
by Pork King April 30, 2003