The Truck Inventory and Use Survey (TIUS) provides data on the physical and operational characteristics of the Nation’s truck population. It is based on a probability sample of private and commercial trucks registered (or licensed) in each State during 1992. A sample of over 150,000 trucks were surveyed to measure the universe of over 60 million trucks.

The following types of vehicles were excluded from this survey: those owned by Federal, State, and local governments, ambulances, buses, and motor homes. A small number of the vehicles sampled were determined to be ‘‘out-of-scope’’ of the survey. These cases include but are not limited to: farm tractors, unpowered trailer units, and trucks reported to have been sold, junked, or wrecked prior to the registration year.

Many States allow pickups, small vans, and utility-type vehicles to be registered as either cars or trucks. The passenger car files were searched and any such trucks were included in the universe of trucks from which the sample was selected. Some vehicles such as ‘‘off-highway’’ trucks used exclusively on private property do not have to be registered. These vehicles were not included in the universe and had no chance of being selected.