In Washington, fault in a car accident is determined based on negligence. The process involves gathering evidence such as police reports, witness statements, and accident scene photos. Washington follows a “pure comparative negligence” rule, meaning each party’s degree of fault is assessed, and compensation is adjusted accordingly. Insurance companies and legal professionals often play a crucial role in evaluating the evidence to establish fault. It’s essential to consult with a knowledgeable attorney to navigate the complexities of fault determination and ensure fair compensation.