Many countries have laws that require the use of booster seats. In the United States of America children under 57 inches (145 cm) and younger than 9 years old have to use a booster seat. Many European countries require a booster seat until the child is either twelve years old or 59 inches tall. There are some exceptions. In the United Kingdom for example children are allowed to ride without a booster seat when they are 53 inches tall and in Austria children who are not 59 inches tall have to use a booster seat until their 14th birthday. However booster seats are used to keep children safe, not because of a law. In general no child can ride safely in a car without booster seat when he is not 57 inches tall. It is proved that children under 57 inches who do not use a booster seat are more likely to suffer serious injuries or even death in the event of an accident. 