Washington is not a no-fault insurance state but a fault insurance state. This means in Washington, each party involved in a car accident is liable for damages and injuries according to each party's degree of fault.
Unlike no-fault states where the injured party's insurance company pays upfront for injuries and damages, fault states require insurance companies to pay according to the degree of fault of those involved in the accident. In fault states, claims adjusters generally determine who's at fault and to what degree, and negotiate payment amounts for injuries and damages. No-fault insurance coverage is less ideal for the injured since coverage tends to be more limited.