Only if they go unpaid
Similar to cell phone, medical or utility bills, credit score formula doesn’t consider parking tickets, and they are not reported to your credit report. However, unpaid parking tickets become unpaid debts and as such are reported to the credit bureaus and do go on your credit report.
Furthermore, unpaid parking tickets usually result in a law suit being filed against you, and in many cases a judgment follows. Judgments tent to have bad impact on credit scores, not to mention the added fines, interest & legal costs. If left unpaid, judgments turn into liens or even a garnish, which further impacts your credit score.
My recommendation is to pay off parking tickets or take legal action if you believe they are unjust, but never simply leave them unpaid.
See cellular-phones-and-credit-score.html for more information.