FHWA Classification

What does 'classification' mean?

In traffic terms, a vehicle's 'classification' is the category it is sorted into based on its physical characteristics. Most classification studies are done use the Federal Highway Administration's Scheme F as a basis. This scheme contains 13 separate classes of vehicles, described below:

 

 

Class 1 - Motorcycles

This class includes all two- or three-wheeled motorized vehicles. These vehicles typically have a saddle-type of seat and are steered by handlebars rather than a steering wheel. This includes motorcycles, motor scooters, mopeds, motor-powered bicycles and three-wheel motorcycles.

 

 

Class 2 - Passenger cars

This class includes all sedans, coupes and station wagons manufactured primarily for the purpose of carrying passengers, including those pulling recreational or other light trailers.

 

 

 

Class 3 - Pickups, Vans and other 2-axle, 4-tire single unit vehicles

This class includes all two-axle, four tire vehicles other than passenger cars, which includes pickups, vans, campers, small motor homes, ambulances, minibuses and carryalls. These types of vehicles which are pulling recreational or other light trailers are included.

 

 

 

Class 4 - Buses

This class includes all vehicles manufactured as traditional passenger-carrying buses with two axles and six tires or three or more axles. This includes only traditional buses, including school and transit buses, functioning as passenger-carrying vehicles. All two-axle, four tire minibuses should be classified as Class 3. Modified buses should be considered to be trucks and classified appropriately.

 

 

 

Class 5 - Two-Axle, Six-Tire Single Unit Trucks

This class includes all vehicles on a single frame which have two axles and dual rear tires. This includes trucks, camping and recreation vehicles, motor homes, etc.

 

Class 6 - Three-Axle Single Unit Trucks

This class includes all vehicles on a single frame which have three axles. This includes trucks, camping and recreation vehicles, motor homes, etc.

 

 

 

Class 7 - Four or More Axle Single Unit Trucks

This class includes all vehicles on a single frame with four or more axles.

 

 

 

 

 

Class 8 - Four or Less Axle Single Trailer Trucks

This class includes all vehicles with four or less axles consisting of two units, in which the pulling unit is a tractor or single unit truck.

 

 

 

 

 

Class 9 - Five-Axle Single Trailer Trucks

This class includes all five-axle vehicles consisting of two units in which the pulling unit is a tractor or single unit truck.

 

 

 

Class 10 - Six or More Axle Single Trailer Trucks

This class includes all vehicles with six or more axles consisting of two units in which the pulling unit is a tractor or single unit truck.

 

 

Class 11 - Five or Less Axle Multi-Trailer Trucks

This class includes all vehicles with five or less axles consisting of three or more units in which the pulling unit is a tractor or single unit truck.

 

 

Class 12 - Six-Axle Multi-Trailer Trucks

This class includes all six-axle vehicles consisting of three or more units in which the pulling unit is a tractor or single unit truck.

 

 

Class 13 - Seven or More Axle Multi-Trailer Trucks

This class includes all vehicles with seven or more axles consisting of three or more units in which the pulling unit is a tractor or single unit truck.

What are unclassified vehicles?

Most class studies also contain data for Class 14 - Unclassified Vehicles. This class includes all vehicles which could not process into one of the existing 13 classes. This data can be retained in your reports, or it can be redistributed by the software into the existing 13 classes based on the percentages in each of those classes.

What causes unclassified vehicles to occur?

If data contains a large amount of unclassified vehicles (20 percent or more), the cause is usually due to either a problem with how the traffic data recorder was programmed for the data collection, or a problem with the road tubes used.

 

If the traffic data recorder has been programmed correctly, and the road tubes used were in good shape and installed correctly, there is usually a small percentage of unclassified data that occurs with any data collection. This percentage can vary, based on a number of factors.

 

When recording one lane of traffic data, unclassified vehicles are usually the result of vehicles striking the road tubes on an angle, or not generating a large enough air pulse to register on the traffic data recorder. In both of these cases, this can cause an axle pattern that is unrecognizable and can’t be sorted into one of the class scheme’s categories. Although accuracy standards vary widely, one rule of thumb is that the percentage of unclassified vehicles for recording one lane should be less than 5 percent to be considered accurate.

 

When recording two lanes of traffic data, unclassified vehicles can result from the same causes as one lane data collection. However, another source of error is from vehicles in opposite lanes both hitting the road tubes at the same time. This can cause an axle pattern that is unrecognizable and can’t be sorted into one of the class scheme’s categories. Again, although accuracy standards vary widely, one rule of thumb is that the percentage of unclassified vehicles for recording two lanes should be less than 10 percent to be considered accurate.

JAMAR Technologies, Inc. 1500 Industry Rd, Suite C, Hatfield, PA 19440

 

Phone: 215-361-2244     Fax: 215-361-2267     E-Mail: mail@jamartech.com