This information is given for educational purposes only. No attorney-client relationship exists between us.
I don't know about Washington, but several places in Texas will report an unpaid traffic ticket, such as a red light camera violation, on a credit report if the fine is not paid. In those cases, you can't get rid of the negative remark without paying the fine or waiting 7 years for the remark to expire.
I suggest you contact the company holding the ticket as tell them you will pay it in full provided they removed it from your report. Get it in writing if possible. If that fails you won't get it removed but you could put a comment on your report about it