Officers from the county's road policing group tracked down the trio after reports of "suspect males" waving down motorists on the A168, which links Northallerton and Wetherby.
Police said an elderly woman had been taken to a cashpoint by the men who were flagging down drivers.
A car was also seized as part of the ongoing investigation.
The incident was the latest in a number of roadside scams reported across the county this year.
They typically involve people waving down other motorists before claiming that they have run out of petrol and need money.
In some cases the fraudsters offer to exchange gold items for the money.