Illinois is a faultbased state when it comes to vehicle accident claims. Another term for this that you may see used is "tort-based."Let Staver Accident Injury Lawyers explain your rights and how to prove liability in a personal injury case. Free Consults: (312) 236-2900. There is no negligence without a "duty. " People or companies must owe you a duty in order for them to negligent and therefore liable. The Illinois Tort Immunity Act is a state law that limits the liability of certain government entities and employees in civil lawsuits. Illinois follows an atfault insurance system, which means that the driver who is responsible for causing the accident is liable for the damages. No, Illinois is not a no-fault state – the state of Illinois adheres to a traditional fault-based system, also called a tort liability system. Illinois follows a modified comparative negligence rule when you're also at fault.