In America, a compact car is defined by cubic feet of interior space
What makes a car compact? In the United States the answer is a number: the Environmental Protection Agency counts combined passenger and cargo volume, and anything between 100 and 109 cubic feet qualifies. Europe prefers lettered segments with no formal size limits, and Britain has its own words again, so one car can wear three labels.
The ladder begins with microcars and their Japanese cousins, kei cars, which sit on the line between car and motorbike. They often have engines of 700 cc or less, three or four wheels, and looser licensing rules. Microcars took off in postwar Europe, descended from earlier voiturettes and cyclecars, while Japan has had kei cars since 1949. Above them sits the smallest class registered as ordinary cars: the European A-segment, or city car, which the EPA calls minicompact, a term few Americans actually use. Such cars date to the early 1920s but boomed in the late 1950s with the original Fiat 500 and BMC Mini.
One step up, the same class goes by three names. Europe says B-segment, Britain says supermini, and America says subcompact, which the EPA defines as 85 to 99 cubic feet. Early British superminis included the 1977 Ford Fiesta and Vauxhall Chevette, while America's first home-built subcompacts, the AMC Gremlin, Chevrolet Vega and Ford Pinto, all arrived in 1970. Next come the C-segment compacts, then the D-segment large family car that Americans call mid-size, at 110 to 119 cubic feet.
Passenger carriers follow their own path. The American minivan, known in Britain as a multi-purpose vehicle or people carrier, is built around flexible rear seating, high roofs, flat floors and sliding doors. Large versions caught on after the 1984 Renault Espace and Dodge Caravan, and smaller compact and mini versions spread from the 1990s, compact ones remaining mostly a European habit.
Luxury has its own rungs. The smallest, the premium compact, became popular in the mid-2000s when Audi, BMW and Mercedes-Benz launched entry models cheaper than their compact executive cars. Above those come executive cars in the E-segment and then full-size luxury saloons. An international standard, ISO 3833 from 1977, also sets out terms for road vehicle types.
Source: Car classification
