From the Oregon Legislature Clerk of the House website:
“In 1999, the Legislative Assembly adopted ORS 171.022, which reads, “Except as otherwise provided in the Act, an Act of the Legislative Assembly takes effect on January 1 of the year after passage of the Act.”
Some bills contain a clause which specify a particular effective date. Still others may have emergency, sunset, or referendum clauses attached.”
See also previous OLR Blog post on effective dates of legislation.