Spitting on city buses is outlawed.

Listing 10.10.100 Unlawful Bus Conduct.

B. A person is guilty of unlawful bus conduct if, while on or in a municipal transit vehicle as defined by RCW 46.04.355, or in or at a municipal transit station as defined in subsection C, and with knowledge that such conduct is prohibited, the person

4. spits or expectorates;