For some reason tickets come in pairs and trios. Be extra careful.
I ALWAYS take traffic court to keep the one point off my record. It about $39 of good insurance.
That lawyer gave you good advice - pay the ticket. A lawyer can't guarantee ANYTHING (except to add his fees).
Quite often you can bargain with the judge (instead of going to a trial) to have the offence lessened and the fine reduced (if you have a good record). Ask for payments.
EDIT: Carpool lane violation . . . hmm. I don't know if theris any discretion allowed the judge. Look up the DMV statute. I imagine $281 is the maximum, not minimum fine. If you have a good record, are really polite and have a reasonable "excuse" (and a "never again, I'll be more careful, your honor"

you may pay much much less.
Good luck!