sentences:  Typically, residents in the zone pay a small fee to the government in exchange for a placard or sticker placed on their automobile(s) that indicates the zone designation (signified by a number or letter).In the United States, residential zoned parking was challenged in 1977 as violating the constitutional right of equal protection of the laws, because it favored one group of people (nearby residents) over another group of people (commuters).However, the United States Supreme Court ruled that the practice did not violate Equal Protection.