OLYMPIA, Wash. — In the drizzly Pacific Northwest, what could be more logical for a business than to hire people to wear oversized raincoats bearing the business name and telephone number and wave at passing motorists?

That's what Kevin Gould, general manager of the Mattress Outlet in Silverdale, thought until 2003, when Kitsap County Superior Court Judge Jay B. Roof ruled that each bright yellow raincoat advertising a half-price sale was "an offsite sign without a permit" in violation of a county ordinance.

That branch of the chain is now closed, but Gould's colorful ad campaign was upheld yesterday as a protected form of commercial speech in a 5-4 ruling by the Washington state Supreme Court.

Besides the majority opinion, which overturned a $1,425 fine, the justices issued two concurrences and a dissent.

In one concurrence, responding to Mattress Outlet's claim that the raincoats should be considered clothing rather than signs, Justice Tom Chambers wrote that the county's reasoning could make his mother liable for wearing logo-bearing sweat shirts and baseball caps. Her shopping bag, which "boldly advertising the name of her favorite department store, is even more suspect," Chambers added.

The majority ruling, however, was based on another Mattress Outlet claim — that the county could not ban off-premises signs promoting commercial services and products like mattresses while allowing those for government-sanctioned festivals, yard sales and political candidates and causes.

The ruling also rejected the county's argument that the raincoats were a "visual blight" and potential traffic hazard.

Not only was there no evidence of any effect on traffic safety, Justice Pro Tem Faith Ireland wrote for the majority, but "raincoat-clad workers are not the type of signage generally thought of as contributing to visual blight."