Good news. You’ve seen the cop shows before where they arrest someone and say “you have the right to remain silent…” Those words really mean something, and they apply here. The Fifth Amendment of the Constitution protects you from EVER being required to assist law enforcement in any way (although if your neighbor is robbed, I recommend you do let them know the license plate number of the sketchy van that was parked outside last night).
In the context of your read light camera ticket, your right to remain silent is very important. First, you do not have to fill out the nomination form that was included on your ticket. Further, the fact that you do not want to reveal the identity of the driver cannot be used against you. (Heck, you might not even know who the driver is anyway.) Finally, just because the car is registered in your name does not make you responsible for the actions of someone else.
If you aren’t the driver, you are my very favorite kind of client: innocent! It’s a very easy ticket for me to get dismissed. I can go to court for you, simply show the judge a picture of your driver’s license compared to someone else driving your car, and the case is dismissed. You do not need to go to court and have any city attorney, cop, or judge pressure you into telling the identity of the driver. Let me do it for you and save the hassle.