Why does it not surprise me that the RFID system in Fastrak is vulnerable to cloning. This article doesn't do a very good job of explaining the problem. A person can walk around a parking lot or drive down the road and war drive for other people's Fastrak ID. There is even a mode to do this silently which is how Caltrans comes up with the driving times data. Once you have those IDs, it turns out that the memory in the actual Fastrak device is read/write which allows a minorly sophisticated techie/hacker to put other people's ID on his device. Granted that to succeed at the fraud you have to block or not care about the photo of your plate (rental car, etc.) but it's still incredibly easy to impersonate someone else. This lack of positive ID should become very interesting to the legal profession.