After three extensions, the state Transportation Department says the end of the day Monday is the deadline to remove studded tires in Washington.
Winter driving conditions in the passes extended the typical deadline of April 1 to April 7 and then the 14th and finally the 25th.
Highway officials say studs cause ruts and damage bridge decks.
Studded tires are typically legal only between Nov. 1 and March 31.
Violators face a $124 fine.