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Definition
Definition
Vehicle Category Classifications, or vehicle classes, is a system that categorizes vehicles into 13 classes based on their axle and tire configuration as well as the number of trailers being pulled. The system was adopted by the Federal Highway Administration (FHWA) and are "used for geometric design, pavement and bridge design, safety analysis, performance measurement, and environmental impact analysis and other programs." Refer to the FHWA Traffic Monitoring Guide, section 1.3.3 for details.
Vehicle Classes and HPMS
Vehicle Classes and HPMS
The Highway Performance Monitoring System (HPMS) report is an annual report on all public roads in the state. The report includes Annual Average Daily Traiffic (AADT), which is a measure of traffic on a roadway segment. In addition to reporting a total AADT count that includes all vehicle classes combined, HPMS also requires AADT for Single Unit Trucks and Combination Unit Trucks.
Single Unit Trucks (Vehicle Classes 4-7) are vehicles where the cab and cargo area are on the same chassis and move as a single unit. Examples include buses, box trucks, and cement trucks.
Combination Unit Trucks (Vehicle Classes 8-13) are vehicles with a tractor (power unit) that has one or more trailers hitched to it. Tractor-trailers are also known as semi-trucks, big rigs, and 18-wheelers.
Refer to the HPMS Field Manual for more information about how AADT is reported for single and combination unit trucks.
Vehicle Class Detailed Definitions
Vehicle Class Detailed Definitions
The following section provides more details about each vehicle type. All definitions are from the FHWA 2013 Traffic Monitoring Guide Appendix C: Vehicle Types.
Passenger Vehicles (Class 1-3)
Passenger Vehicles (Class 1-3)
Class 1: Motorcycles
All two or three-wheeled motorized vehicles. Typical vehicles in this category have saddle type seats and are steered by handlebars rather than steering wheels. This category includes motorcycles, motor scooters, mopeds, motor-powered bicycles, and three-wheel motorcycles.
Class 2: Passenger Cars
All sedans, coupes, and station wagons manufactured primarily for the purpose of carrying passengers and including those passenger cars pulling recreational or other light trailers.
Class 3: Pickup Trucks, Vans, and Other 2-Axle, 4-Tire, Single Chassis Vehicles
All two-axle, four-tire, vehicles, other than passenger cars. Included in this classification are pickups, panels, vans, and other vehicles. Examples include campers, motor homes, ambulances, and minibuses.
Single Unit Trucks (Class 4-7)
Single Unit Trucks (Class 4-7)
Class 4: Buses
All vehicles manufactured as traditional passenger-carrying buses with two axles and six tires or three or more axles. This category includes only traditional buses (including school buses) functioning as passenger-carrying vehicles. Modified buses should be considered to be a truck and should be appropriately classified.
Class 5: Single Unit Trucks (2-Axles, Dual Rear Wheels)
All vehicles on a single frame with two axles and dual rear wheels. These are similar to class 3 trucks except for the dual rear wheels.
Class 6: Single Unit Trucks (3-Axles)
All vehicles on a single frame with three axles.
Class 7: Single Unit Trucks (4+ Axles)
All vehicles on a single frame with four or more axles
Combination Unit Trucks (Class 8-13)
Combination Unit Trucks (Class 8-13)
Class 8: Combination Trucks (4 or Fewer Axles, Single Trailer)
All vehicles with four or fewer axles consisting of two units, one of which is a tractor or straight truck power unit.
Class 9: Combination Truck (5 Axles, Single Trailer)
All five-axle vehicles consisting of two units, one of which is a tractor or straight truck power unit.
Class 10: Combination Truck (6+ Axels, Single Trailer)
All vehicles with six or more axles consisting of two units, one of which is a tractor or straight truck power unit.
Class 11: Combination Truck (5 or Fewer Axles, Multiple Trailers)
All vehicles with five or fewer axles consisting of three or more units, one of which is a tractor or straight truck power unit.
Class 12: Combination Truck (6 Axles, Multiple Trailers)
All six-axle vehicles consisting of three or more units, one of which is a tractor or straight truck power unit
Class 13: Combination Truck (7+ Axles, Multiple Trailers)
All vehicles with seven or more axles consisting of three or more units, one of which is a tractor or straight truck power unit.
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