Washington state requires vehicle owners to have automobile insurance on their vehicles. Drivers are only required to have $25,000 per person and $50,000 per accident in liability insurance. Liability coverage pays for damages associated with injuries to another vehicle's passengers.
Driver's are also required to have $10,000 in property damage coverage to pay for repairs to a vehicle.
Here's the state law - RCW 46.30.020 and RCW 46.29.090.