Yes, I think you're right.
Thank you for accepting. I'll keep writing to you. I suggest that you contact the city IN WRITING, and that your letter should be signed and dated by you and several of your fellow owners, if possible. Keep copies, of course. From what you have told me so far, I can't believe that the HOA would have jurisdiction to govern who parks where on a city or county street. However, the city/county and your HOA may have some type of signed agreement in which the HOA has been given authority over the streets in exchange for something or another. When you write to the government office, ask them if there are any agreements. Ask for a reply within 14 days. Send the letter by certified, return receipt mail (about $5.50). If several people sign, you can split the cost.
I'm curious - has anyone who has parked on the street ever gotten towed or a ticket from the city/county? Or just a notice from the HOA? If the latter, it may well be unenforceable.
Now, if you don't get a reply, send a certified letter to the mayor or city council or city manager, enclosing a copy of the first letter you sent, stating in your cover letter that you have not received a reply. If you still don't hear back, go to your local media - a consumer reporter at a newspaper or tv station or radio station may be willing to publicize this story.
Finally, as a very last resort, a few of you may want to pool your money and hire a real estate attorney who specializes in condos/HOA's to file a lawsuit seeking an injunction (restraining order) against the HOA to prevent them from trying to enforce this parking rule. Don't hire an attorney without first checking references, like you would for any expensive employee.
May I be of further help?
I'm going to take a break, and will check back in an hour or so.