A few years ago I was talking to a friend (a lawyer who was public defender for a while & also involved in local politics) about red light cameras.
He told me that cameras cannot testify against you in court. Said that you have the right to question your accuser and that accuser is not able to answer. He said a technician did not count, because then it basically is hearsay.
The town politicians realized the red light camera tickets were a losing battle in court.
Their solution? They simply reduced the fine until it got to the point where most people paid instead of fighting the tickets. It was better for most to pay rather than taking the time off of work to go to court.