Or. Rev. Stat. § 816.310.

This section establishes exemptions from ORS 816.040 to 816.300. The exemptions under this section are in addition to any exemptions under ORS 801.026. The exemptions established under this section are partial or complete as described in the following: (1) ORS 816.040 to 816.300 shall not be construed to prohibit the use of additional parts and accessories on any vehicle not inconsistent with the provisions of those sections. (2) Lighting equipment used on vehicles of special interest that are registered under ORS 805.020 shall be deemed in compliance with ORS 816.040 to 816.300 if the equipment is original manufacturer’s equipment and accessories, or their equivalent and if the equipment is maintained in safe operating condition. (3) ORS 816.040 to 816.300 do not apply to equipment on any of the following: (a) Road machinery. (b) Road rollers. (c) Farm tractors. (d) Antique vehicles that are maintained as a collector’s item and used for exhibitions, parades, club activities and similar uses, but not used primarily for the transportation of persons or property. (e) Motorized wheelchairs when used as permitted under ORS 811.440. (4) On any combination of vehicles, only the lighting equipment on the rearmost vehicle in the combination of vehicles need be visible from distances specified under ORS 816.040 to 816.290 for lighting equipment on the rear of vehicles. (5) Lighting equipment on bicycles shall meet the requirements established for such equipment under ORS 815.280. (6) Vehicle lighting equipment requirements for ambulances, organ transport vehicles and emergency vehicles are established in ORS 820.350. (7) Lighting equipment on electric personal assistive mobility devices shall meet the requirements established in ORS 815.284.