Restrictor plates are devices installed between the carburetor and intake manifold that restrict the amount of air and fuel entering the engine's combustion chamber. They are used in NASCAR racing at the two longest superspeedways, Daytona and Talladega. The device limits the power output of the motor and hence slows both the acceleration and the overall top speeds obtainable on the tracks where the cars are so equipped. These restrictions are supposedly in the interest of driver and fan safety, although many members of both of those groups feel that the close packing of cars and their inability to achieve separation may actually make the racing at these tracks more dangerous than before the restrictor-plate rules were implemented in the 1980s, as there are often massive and frightening multi-car pileups during those races. It certainly makes for a different style of racing at these events than that which occurs at the other superspeedways used by NASCAR, as reduced power make it more difficult to pass other drivers. Drivers often form long chains, which, due to the lack of air resistance, typically travel faster than single cars. This type of racing is often referred to by fans, drivers, and crew members alike as restrictor plate racing.