Legal analysis: The accident liability determination letter issued by the traffic police does not require the signature and approval of both parties. If signature is required, it should be delivered and signed for. The other party's failure to sign has nothing to do with the outcome of the accident liability determination. If the other party disagrees with the result of the liability determination, it can only appeal to the superior.

Legal basis: "Regulations on Procedures for Handling Road Traffic Accidents" Article 60 The traffic management department of the public security organ shall determine the party's liability based on the role of the party's behavior in the occurrence of the road traffic accident and the severity of the fault. responsibility.

(1) If a road traffic accident occurs due to the fault of one party, the party shall bear full responsibility;

(2) If a road traffic accident occurs due to the fault of two or more parties , according to the role of their actions in the accident and the severity of their faults, they shall bear primary responsibility, equal responsibility and secondary responsibility respectively;

(3) None of the parties was at fault for causing the road traffic accident and it was a traffic accident. In the event of an accident, neither party will be held responsible.

If one party intentionally causes a road traffic accident, the other party is not responsible.