89% of households in the USA owned one or more cars. About one quarter of all households in the outer suburbs of Washington DC owned three or more cars in 1990. Nearly 80% of people aged 16-and-older had a car for personal use, up from 74% in 1980. Cars have become so numerous on high school campuses that some principals have ordered rationing of parking spaces or are charging fees to discourage use. In some neighbourhoods where parking space is tight, car owners are parking their extra cars in fire lanes or in their gardens.