Should I pay for a ticket that I no longer own?

Did you transfer title to the coworker? Sounds like not.
Do you not have any contact with the co-worker? Unless ownership of the vehicle was properly transferred to your name, you might be stuck.

I would suggest humbly explaining the situation in court and hope that the judge or referree will see the reality of the situation despite that you may show up as the owner of record.

Hi,
As another said, you might be stuck with the fines.
Sounds like you are still the legal owner of the vehicle. If you did not sign over your vehicle title to your co-worker, you are probably out of luck. Just turning over the license plates to the proper people does not mean you still don't own the vehicle. It simply means it won't be driven by you anymore.
The judge might be lenient with the fines, or reducing them some, IF you have written proof of some kind that you "donated" the vehicle to someone else.
I do wish you the best of luck.

Your friend is using "YOUR" car, he has borrowed it, unless you have a bill of sale ( even for one dollar) you can not donate a car to him, since he is not a donation center. Even then a donation center gives you a reciept for the car ( althought they often don't retitle the car) so you have to keep your recept.

You could be liable for many things that your friend does with the car, since you are the legal owner, if he has an accident for example and kills someone, guess who could be added to the law suit since you are shown by the state to be the legal owner.

This is assumeing you did not trasfer the title of the car over to him.

The state keeps records of ownership by VIN, last known plate number and car model and make, along with other information.

So you got the tickets because it was traced toyou by the VIN number.

You need to get the title of this car transferred to your friend.

Next the tickets will not go away, they will stay on "YOUR" record. And you will find in many areas the fines grow and grow and grow.
So you need to talk to the court and clear this up.

Since your friend got a ticket for no plate(tag) and the such it is obvious he has not gotten the car registered in his name and is merely driving your car knowing if anything happens you will be held resonible not him.