As a pedestrian, you do have a duty to obey all traffic and pedestrian signals, signs, and laws. If you fail to follow the law, you can get a ticket for jaywalking. If you're hit by a vehicle as a pedestrian while jay walking you may still have a case.
In a Washington pedestrian accident with a car or other motor vehicle you can bring a lawsuit against the driver of the motor vehicle even if you are partially responsible for your pedestrian accident. So in the case of jay walking you could have a case against the driver who hit you but you would be facing a problem down the road with trying to figure out a division of fault. In such cases it's a very good idea to speak with an experienced and knowledgeable Washington pedestrian accident attorney.