Chapter 4 of 518% of exam
Speed & Conditions
Posted limits are set for good conditions, and Washington's basic speed law expects you to slow down when the road or weather is poor. Choosing a safe speed is one of the most important driving decisions.
Common limits
Unless otherwise posted, residential and business districts are commonly 25 mph, while some interstates are posted up to 70 mph. Always obey the posted signs, which set the legal maximum.
Basic speed law
You must drive at a speed that is reasonable and prudent for actual conditions, even if that is below the posted limit. Traffic, weather, and visibility all affect a safe speed.
Adjusting to conditions
In rain, fog, or on icy roads, reduce your speed and increase your following distance because traction and visibility drop. Brake gently and avoid sudden steering on slick surfaces.