734-074-0008 Definitions As used in Division 74 rules: (1) “Auxiliary axle” is an axle that qualifies as a booster axle, flip axle or lift axle and when attached to the rear of a trailer shall be included in the measurement of the trailer. (2) “Booster Axles(s)” means a separate vehicle bolted or pinned to another vehicle that redistributes weight from one or more axles to other axles and pivots from side to side at the connection point or has wheels that steer during turning. (3) “CCD” means the Commerce and Compliance Division of the Oregon Department of Transportation. (4) “Converter dolly” means those devices towed behind a vehicle and used to convert a semitrailer to function as a self-supporting trailer. (5) “Dromedary truck-tractor” means a motor truck designed to carry a load and also pull a semitrailer by using a kingpin to fifth wheel connection. Unless specifically authorized, a dromedary truck-tractor may not tow a stinger steered trailer. (6) “Flip axle” means an axle that is bolted or pinned to a vehicle and flips from the closed position on the trailer to a deployed position on the ground extending the length and hauling capacity of the trailer. (7) “Idle Reduction System” means an auxiliary power unit or other device or technology that is used to reduce long-duration idling by allowing the main drive engine or auxiliary refrigeration engine to be shut down. (8) “Lift Axle” means an axle(s) that can be raised from or lowered to the surface of the ground. (9) “Motor Truck” means a motor vehicle that is primarily designed or used for carrying loads other than passengers. (10) “New generation wide base single tire” means a tire that has a nominal section width over 14 inches and a ratio of width to height less than or equal to 55. (11) “Reasonably uniform in length” as used in ORS 818.210, means a variance of not more than eight feet from the longest to shortest self-supporting trailers or semitrailers within the authorized combination of vehicles. It does not include the length of a converter dolly when used to convert a semitrailer to a self-supporting trailer. (12) “Tandem drive axles” means two or more axles spaced more than 40 inches but not more than 96 inches apart, neither of which can be raised from the surface of the ground, and where no one axle carries less than forty percent (40%) of the tandem axle weight. Each axle of a tandem drive axle shall have four tires or each axle may have two tires if tire width is at least 15 inches and each axle transmits motive power to the road surface. Any weight controls for the tandem axles on a power unit must be designed, installed and used such that the axles always distribute the load so no axle, tandem axle or group of axles exceeds the legal weight limits or bridge formula limits. All axle assemblies of the tandem drive axles (including axles, tires, brakes) must be adequate to carry the weight loading but may not have less than a 20,000 pound rating for each axle. (13) “Truck-Tractor” means a motor vehicle designed and used primarily for drawing (towing) other vehicles and constructed so as not to carry any load other than a part of the weight of the vehicle or load, or both, as drawn. (14) “Variable-load suspension axle” means an axle that can vary the amount of weight being transmitted to the surface of the road by adjustments made by the driver. Examples of adjustments available to the driver include, but are not limited to, the use of tool(s), lock and key, pressure regulators with handles or knobs. The term variable load suspension axle does not include use of devices such as height control valves, axles controlled by devices that raise the axle when the vehicle moves backward or pre-set pressure regulators which are not adjustable by the driver. Statutory/Other Authority: ORS 184.619 & 818.220 Statutes/Other Implemented: ORS 818.200 & 818.220 History: DOD 1-2025, amend filed 03/13/2025, effective 03/13/2025 HWD 21-2020, minor correction filed 05/21/2020, effective 05/21/2020 HWD 2-2010, f. & cert. ef. 3-17-10 HWD 6-2007, f. & cert. ef. 10-17-07 HWD 2-2005, f. & cert. ef. 3-18-05 TO 2-2001, f. & cert. ef. 6-14-01 HWY 8-1997, f. & cert. ef. 8-26-97 HWY 3-1995, f. & cert. ef. 10-16-95