Washington Administrative Code › Title 468 - Transportation, Department of (See Title 88) › Chapter 468-38 - Vehicle size and weight-Highway restrictions-Equipment › Section 468-38-005 - Definitions

Current through Register Vol. 24-14, July 15, 2024
What vehicle size and weight words and phrases are used
				commonly in addition to those codified in
				chapter
				46.04 RCW?
A-dolly:
A converter dolly that is towed from a
				single hitch at the center line of the tow vehicle and contains the lower half
				of the fifth wheel assembly that when connected by kingpin to a semi-trailer
				converts the combined configuration into a full trailer.
A-train double:
A combination of vehicles composed
				of a tractor, a semi-trailer and either an A-dolly and a semi-trailer or a full
				trailer attached to the rear of the forward semi-trailer as if an A-dolly were
				used.
Axle:
The common axis of rotation of one or more
				wheels, either power-driven or freely rotating, in one or more segments in the
				same transverse plan. (Expanded from the definition in chapter 46.04.060
				RCW.)
Axle group:
Any set of two or more parallel axles
				associated with a single vehicle or vehicle combination.
Axle group weight:
The part of the gross vehicle
				weight transmitted to the highway by the defined axle group.
Axle spacing (spread):
The longitudinal distance
				between the centers of the foremost and rearmost axles of an axle group
				measured from center to center of the defined axles.
B-train double:
A combination of vehicles composed
				of a tractor, a semi-trailer and a second semi-trailer connected by kingpin to
				the lower half of a fifth wheel assembly mounted on the rear of the forward
				semi-trailer.
C-dolly:
A converter dolly that is equipped with a
				single axle that is self-steering, towed from two hitches located in a
				horizontal transverse line on the towing unit, and is so designed that when the
				trailer converter dolly is coupled to a towing trailer, the trailer converter
				dolly cannot pivot horizontally with respect to the towing trailer.
Axle spacing report:
A report stating the maximum
				amount of weight a vehicle, or vehicle combination, can carry, both legally and
				under permit, based on the number of axles, the axle spacings, and the number
				and sizes of tires on the vehicle, or vehicle combination.
Combination length:
The total length of a
				combination of vehicles, i.e., truck-tractor -- semi-trailer -- trailer
				combination, measured from front extremity of the first vehicle to the rear
				extremity of the last vehicle, including the connecting space between vehicles
				and any overhanging load.
Combined trailer length:
The total length of a
				combination of trailers measured from the front extremity of the first trailer
				to the rear extremity of the last trailer including the connecting space and
				any overhanging load.
Converter dolly:
A vehicle unit that is designed,
				usually with the bottom half of a fifth wheel assembly, to convert a
				semi-trailer with kingpin into a full trailer.
C-train double:
A combination of vehicles composed
				of a tractor, a semi-trailer, a C-dolly and a second semi-trailer.
Daylight hours:
One-half hour before sunrise until
				one-half hour after sunset.
Extra-legal vehicle:
A vehicle, laden or unladen,
				which exceeds legal dimensions and/or weights and operates on highways by
				permit.
Gross weight:
The weight of a vehicle and/or
				combination of vehicles plus the weight of any load thereon.
Height:
The total vertical dimension of a vehicle
				above the ground surface including any load or appurtenance.
Length:
The total longitudinal dimension of a
				single vehicle, vehicle combination (see combination length), or individual
				trailer or semi-trailer. Trailer length is measured from the front of the
				cargo-carrying unit to its rear, exclusive of all overhangs from safety or
				energy efficiency devices (see also measurement exclusive devices). Length of a
				loaded trailer must include any overhangs of load when determining compliance
				with length limits or the need for a special permit.
Longer combination vehicle:
A combination of truck
				tractor, semi-trailer, and trailer that exceeds legal length dimensions and
				operates on highways by permit for transporting reducible loads.
Maximum off track:
The maximum difference in the
				path created by the center of the steering axle and the center of the rearmost
				axle of the vehicle or vehicle combination during the negotiation of a
				turn.
Multilane highway:
A highway with two or more
				lanes of travel in the same direction.
Measurement exclusive devices:
Certain devices
				that provide added safety, energy conservation, or are otherwise necessary, and
				are not designed to carry cargo.
National network:
Those interstate and other
				federal-aid primary highways on which commercial vehicles of the dimensions
				authorized by the Surface Transportation Assistance Act of 1982 are allowed to
				operate.
Night:
Night means one-half hour after sunset to
				one-half hour before sunrise.
Nondivisible load:
A load that cannot be readily
				or reasonably dismantled and is reduced to a minimum practical size and weight.
				Portions of a load can be detached and reloaded on the same hauling unit when
				the separate pieces are necessary to the operation of the machine or equipment
				which is being hauled: Provided, That the arrangement does not exceed permit
				limits for the configuration without the reloaded pieces. The federal
				definition of nondivisible load to be used for vehicles operating on the
				interstate is as follows: Any load or vehicle exceeding applicable length or
				weight limits that, if separated into smaller loads or vehicles, would:
				Compromise the intended use of the vehicle, destroy the value of the load or
				vehicle, require more than eight work hours to dismantle using appropriate
				equipment.
Permit:
A written or electronic authorization
				to:
(a) Move or operate a vehicle, or
			 combination of vehicles, on a highway;
(b) With or without a load;
(c) Of size and/or weight exceeding the
			 limits prescribed for vehicles in regular operation.
Pilot/escort vehicle:
A motor vehicle used for the
				express purpose as a warning and guide vehicle for extra-legal vehicles.
Pounds per inch of tire width:
A measure of load
				restriction based on rated tire size. The pounds per inch of tire width are
				determined by dividing the weight carried on the axle group by the number of
				tires in the group and dividing again by the manufacturer's rated tire width as
				indicated on the sidewall of the tire.
Rear overhang:
The distance from the center of the
				last axle to the end of the load, or portion of the vehicle whichever is
				longer.
Regional permit:
Permits issued for interstate
				movement of certain nondivisible overweight and/or oversize vehicles and/or
				loads on highways designated by the jurisdictions participating in the
				"
Western Regional Agreement for the Issuance of Permits for Overweight
				and/or Oversize Vehicles and/or Loads Involved in Interstate
				Travel
."
Regular operation:
The movement over highways of
				motor vehicles with dimensions and weights specified by state and federal
				codes.
Retractable axle:
An axle that can be separately
				raised and lowered by the driver of the vehicle but may not have its weight
				bearing capacity regulated from within reach of the driver's compartment. Also
				known as "lift axle" and "booster axle," or more formally known as a "variable
				load suspension" (VLS) axle.
Rocky mountain double:
A combination of vehicles
				including a truck-tractor pulling a long semi-trailer and a shorter
				trailer.
Single axle:
An assembly of two or more wheels
				whose centers are in one transverse vertical plane and which are transmitting
				weight to the highway.
Single unit:
A motor vehicle with no attached
				vehicles, i.e., truck, bus, truck-tractor.
Steering axle:
The axle or axles on the front of a
				motor vehicle that are activated by the operator to directly accomplish
				guidance or steerage of the vehicle and/or a combination of vehicles.
Superload:
A superload is any load that would
				require special analysis and approval by one or more state permit offices
				because of dimensions or weight. Criteria for superloads in Washington state
				are found in WAC
				468-38-405.
Tandem axle:
Any two consecutive single axles
				whose centers may be included between parallel transverse vertical planes
				spaced at least four feet but not more than eight feet apart, extending across
				the width of the vehicle, articulating from a common attachment, or designed to
				automatically equalize the load between the two axles. This working definition
				is extrapolated from
				RCW
				 46.44.041.
Tote:
Common term for a motor vehicle used to
				transport manufactured housing.
Tridem axle:
Any three consecutive single axles
				whose extreme centers may be included between parallel transverse vertical
				planes spaced not more than twelve feet apart, extending across the width of
				the vehicle, and are articulated from a common attachment to the vehicle, or
				are designed to automatically equalize the load between the three axles.
Truck-tractor:
A motor vehicle used primarily for
				pulling other vehicles but not specifically constructed to carry a load other
				than a part of the weight of the vehicle and load being pulled. This vehicle
				may include a small freight compartment (also referred to as a dromedary box),
				deck or plate not more than eight feet in length used for carrying a load.
				Federal rule allows the interstate use of a vehicle with a dromedary box only
				if the vehicle was in operation prior to December 1, 1982, proof to be provided
				by the vehicle operator. This working definition was extrapolated from
				RCW
				 46.04.655,
				46.44.037 and Code of Federal
				Regulation,  23 C.F.R. 658.13(f).
Trunnion axle:
An axle configuration with two
				individual axles mounted in the same transverse plane, with four tires on each
				axle, connected at a pivot point that allows each individual axle to oscillate
				in a vertical plane to provide constant and equal weight distribution on each
				individual axle.
Trunnion axle group:
Two or more consecutive
				trunnion axles, that are individually attached to, and/or articulated from, the
				vehicle, and may include a weight equalizing suspension system.
Turnpike double:
A combination of vehicles
				including a truck-tractor pulling a long semi-trailer and an additional long
				trailer.
Wide base tire:
A tire whose nominal section
				(sidewall to sidewall) width, as identified by tire nomenclature, is over
				fourteen inches.
Width:
The total outside transverse dimension of a
				vehicle including any load or load-holding devices thereon, but excluding
				approved safety devices and tire bulge due to load.
Statutory Authority:
				  RCW
				  46.44.090. 05-04-053, § 468-38-005,
				  filed 1/28/05, effective 2/28/05.