Originally Posted by
docbert
In general, Hertz do not use transponders. (There are a few states where they do, but VA isn't one of them).
They instead rely on the video-based license plate detection use the toll roads. If your toll is paid by some other means (cash, your own transponder, etc) then the license plate will not be charged, and thus you won't be charged anything by Hertz/Platepass. If you pass through without paying, your license plate photo is taken, which goes to Hertz/Platepass, who then pass it on with the additional fee.
Actually there still are some tolls in VA that still require a transponder such as 267 East and 267 West, the latter being one that won't even let the gate open if your transponder isn't working. Also you are required to have a transponder to use the 495 & 95 HOT lanes in Northern VA, even though it may seem other wise.
I'm not sure about other locations, but at Dulles you can ask the exit attendant to give you a transponder.