"It was just a little overly sensitive and for some people it triggered as three or more axles instead of the two axle passenger vehicle," said ERT spokesperson Leila Rice.
Magnetic sensors underneath the roadways scan vehicles for the number of axles. Two axle vehicles are charged $0.75 in off-peak hours, and vehicles with three or more axles are charged $2.25.
NewsChannel 3 became aware of the problem when two different viewers, who both drive pickup trucks, showed their EZ Pass accounts had been overcharged on several different trips.
"They were mostly westbound at the Downtown Tunnel, that's not to say we didn't see some in the other locations, so they're checking all of them and re-assessing," Rice said.
Rice said the sensor issues will be corrected by the end of the day. They also hope to have Virginia EZ Pass customers refunded by the end of the night. Those who have out-of-state EZ Passes may have to wait another day or two.
As for those who pay by plate, ERT said they process those and should catch any errors before bills go out in the mail.