Legal analysis: traffic police can't enforce the law without wearing police uniforms. According to the relevant laws and regulations of the state, traffic police can wear standard clothes, people's police signs and do not show their certificates when enforcing the law.

Legal basis: Article 52 of the Administrative Punishment Law of the People's Republic of China. If a law enforcement officer makes a decision on administrative punishment on the spot, he shall show his law enforcement certificate to the party concerned, fill in the written decision on administrative punishment in a predetermined format and number, and deliver it to the party concerned on the spot. If the party refuses to sign for it, it shall be indicated in the decision on administrative punishment. The written decision on administrative punishment prescribed in the preceding paragraph shall specify the illegal acts of the parties concerned, the types and basis of administrative punishment, the amount, time and place of the fine, the ways and time limit for applying for administrative reconsideration and bringing an administrative lawsuit, and the name of the administrative organ, and shall be signed or sealed by law enforcement personnel. The decision on administrative punishment made by law enforcement officers on the spot shall be reported to the administrative organ for the record.