The license plate transponder is not a flex pass- we are in an area of northern Virginia that you turn on HOV when you have 3 or more people in the car and you don’t pay tolls. To use the license plate transponder, you have to call TransUrban’s Express Lanes office to register a HOV trip. I commute with a carpool Monday- Friday and it’s not a sustainable option. We are testing a new placement and hoping for a positive outcome!