Truck classifications are typically based upon the maximum loaded weight of the truck, typically using the gross vehicle weight rating (GVWR) and sometimes also the gross trailer weight rating (GTWR), and can vary among jurisdictions. United States In the United States, commercial truck classification is determined based on the vehicle's gross vehicle weight rating (GVWR). The classes are numbered 1 through 8. Trucks are also classified more broadly by the Federal Highway Administration (FHWA), which groups classes 1 and 2 as light duty, 3 through 6 as medium duty, and 7 and 8 as heavy duty. The Environmental Protection Agency (EPA) has a separate system of emissions classifications for trucks. The United States Census Bureau also assigned classifications in its now-discontinued Vehicle Inventory and Use Survey (VIUS) (formerly Truck Inventory and Use Survey (TIUS)). United States federal law requires drivers to have a commercial driver's license (CDL) to operate heavy-duty vehicles (Class 7 and 8) in commerce, with the exception of emergency vehicles and vehicles strictly used for recreational and/or agricultural purposes, though it allows states to require a CDL for these vehicles under their discretion. A CDL is also required to operate any vehicle that transports at least 16 passengers (including the driver) or hazardous materials requiring placards under federal and state law regardless of the weight of the vehicle. States may extend CDL requirements for additional vehicles, for example, New York requires a CDL to operate a stretched limousine and California requires a CDL for any vehicle with three or more axles that has a gross vehicle weight rating of over 6,000 pounds. Table of US GVWR classifications Notes on weight classes "Ton" rating When light-duty trucks were first produced in the United States, they were rated by their payload capacity in tons: (1000 pounds), (1500 pounds) and 1-ton (2000 pounds). Ford had introduced the "One-Tonner" in 1938 to their line of trucks. The "Three-quarter-tonner" appeared in the Ford truck lineup in 1939. Over time, payload capacities for most domestic pickup trucks have increased while the ton titles have stayed the same. The 1948 Ford F-1 had a Gross Vehicle Weight Rating (GVWR) of 4700 pounds. The truck was marketed with a "Nominal Tonnage Rating: Half-Ton." The actual cargo capacity had increased to 1450 pounds. Ford adopted this promotional nomenclature in 1948 to assist buyers, sellers, and users. The now-imprecise ton rating has continued since the post World