In Illinois, fault in a car accident is determined based on negligence. The state follows a “comparative negligence” rule, meaning each party’s level of fault is assessed and assigned a percentage. To establish fault, evidence such as police reports, witness statements, traffic camera footage, and expert testimonies are crucial. Insurance companies and legal professionals analyze this evidence to determine liability. It’s important to note that if you are found to be more than 50% at fault, you may not be eligible to recover damages. Consulting with an experienced car accident attorney can help navigate the complexities of fault determination and ensure your rights are protected.