关于申请美国公民填表要不要报告警察罚单，专业移民网站的解释是肯定的，决定不报是你自己的事。

Traffic violation can affect your citizenship application. While every case is unique, generally USCIS isn’t likely to decline a citizenship petition because the applicant has received speeding. You should, however, pay all your fines and close out all your cases before you file your N-400 petition

If you leave out the traffic tickets from your application, you could be rejected for not having good moral character. This could mean waiting to apply for citizenship in five years.

Because you are required to be truthful on your Form N-400, you must report all the traffic tickets you have received. Every case is unique, so tickets on your record can affect your citizenship petition – specifically if they’re crimes.

https://www.passage.law/blog/disclose-traffic-and-other-minor-violations-on-your-n-400/

另外，移民局官方网站有说明，如果是严重的交通肇事，还必需提供相关的事故报告备查。