RCW Code Description Link
46.04.071 A Bicycle is defined as a human powered device with 2 wheels bigger than 16 inches.
46.61.050 Bicycles must obey traffic lights and stop signs (as well as all other traffic control devices)
46.61.110 Overtaking on the Left (“Safe passing”)
46.61.126 Bicycles & Pedestrians must follow traffic laws
46.61.160 Bicycles cannot ride on some limited access highways
bikes forbidden: SR 520, I-405, I-90 (exit 0 to exit 17), I-5 (Lakewood to Marysville), parts of 18, 518, 522 & 599 and a few others.
46.61.261 A bicycle must yield to a pedestrian on a sidewalk or crosswalk.
46.61.700 Parents are responsible for kids obeying bike laws
46.61.710 Mopeds and gas powered bikes & scoters are not allowed on sidewalks or trails.
46.61.710 Electric-assist bicycles allowed on sidewalks and trails but maybe locally forbidden.
46.61.723 Fully electric powered bikes are not allowed on sidewalks or trails.
46.61.750 Bicyclists riding on roads must obey all traffic laws.
46.61.750 Bicyclists may be ticketed for violating traffic laws
46.61.750 Traffic laws apply on bicycle trails too.
46.61.755 Bicycles have all the same RIGHTS and RESPONSIBILITIES as cars.
46.61.755 A bicycle is a vehicle on the road or a pedestrian on the sidewalk
46.61.758 Must signal turns with left hand (right=up, left=out, stop=down). But Right hand signal for right turn is an acceptable substitute.
46.61.760 Only one person per bicycle seat.
46.61.765 Clinging to vehicles is illegal
46.61.770 Ride as far to the right as is safe and practical except when turning or passing.
46.61.770 Bicycles are not required to use a bike lane or shoulder.
46.61.770 Bicycles can and should use turn lanes
46.61.770 Bicycles can ride on the left (with the traffic flow) on one way streets.
46.61.770 Can ride 2 abreast, not more.
46.61.770 Can legally take the lane if necessary.
46.61.775 Must have at least one hand on the handlebars at all times
46.61.775 Cannot ride carrying anything with both hands while riding.
46.61.780 Bikes must have brakes
46.61.780 At night, bikes must have white light on front, red reflector on the back.
46.61.780 Steady or flashing red rear light may be used in addition to the reflector.
46.61.790 Legal to bicycle drunk, but police may impound bicycle if you are too drunk.

Some state laws for cars which are useful for bicyclists to know:

RCW Code Description Link
46.04.197 A Highway is defined as the width of every public roadway between property lines.
46.04.500 A Roadway is defined as a highway excluding sidewalk & shoulder.
46.04.670 A Vehicle is defined as a device capable of being moved upon a public highway.
46.04.670 Bicycles are defined as vehicles.
46.61.115(b) It is OK to pass cars on the right if safe & there’s space for bicycle traffic
46.61.125(1)(d) Car must yield to oncoming bicycle if passing.
46.61.135(3) Illegal to go left around traffic circles.
46.61.185 Vehicle turning left must yield to all oncoming vehicles going straight
46.61.205 A car on a private road or driveway must yield to all vehicles approaching.
46.61.235 Illegal to pass a car stopped for a pedestrian or bicycle.
46.61.261 Car must yield to bicycle on sidewalk
46.61.400 Max speed: 25 MPH on city streets, 50 on county roads, 60 on state highways
46.61.425 May go slow & impede traffic if necessary for safety.
46.61.425 May exceed speed limit briefly to pass slow vehicle.
46.61.427 Must pull out where safe if five or more vehicles delayed on a 2 lane hwy.
46.61.445 Due care is required!
46.61.500 Driving in willful or wanton disregard for the safety of persons or property
46.61.606 Cars can’t drive on sidewalk
46.61.620 Check before opening car door. Don’t leave car door open.
46.61.667 Driver may not hold a celphone to their ear. (effective Jul 1 08)
46.61.668 Driver may not send, read or write text message except in emergency.
46.61.670 Illegal for car to drive with 2 or 4 wheels off pavement.

Source: https://wabikes.org/growing-bicycling/washington-bike-laws/bicycle-laws-safety-revised-code-of-washington-state-bicycle-related/