Or. Rev. Stat. § 810.260
(1) The Department of Transportation shall adopt standards for the installation, operation and use of traffic control signal operating devices authorized under ORS 815.445. In adopting standards, the department shall consider the impact of traffic control signal operating devices on:
(2) The Department of Transportation shall adopt rules establishing priorities and preemptive use among users of traffic control signal operating devices. The rules shall take into account:
[1997 c.507 §5]