SUNSET PARK - Some Sunset Park and Bay Ridge livery cab drivers say a counterfeit money scam threatens to drive them out of business.

The State Federation of Taxi Drivers says passengers have used thousands of fake $20 bills to get real change from drivers. The federation also says local bodegas and restaurants are being ripped off.

Cab officials say the bills all have the same serial number. Drivers are urged to use money markers that detect fake bills by turning them a dark color.